Patent Abstract:
A semiconductor device has a smaller area. That is, in a row selection decoder including MOS transistors, which selectively connect a plurality of selection signal lines to row selection lines of NAND flash memories having an SGT structure, the MOS transistors are formed on a planar silicon layer that is formed on a substrate, and each have a structure such that a drain, a gate, and a source are disposed in the vertical direction and the gate surrounds a silicon pillar. The planar silicon layer is formed of a first activation region of a first conductivity type and a second activation region of a second conductivity type, and the first and second activation regions are connected with each other via a silicide layer formed on the surface of the planar silicon layer.

Full Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present invention contains subject matter related to Japanese Patent Application No. 2014-008002 filed in the Japan Patent Office on Jan. 20, 2014, the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The present invention relates to a semiconductor device. 
         [0003]    Recently, the miniaturization of bulk memories, typically, NAND flash memories, has seemed to approach its limit. In order to further lower the price per bit, various NAND flash memories having a three-dimensional structure have been proposed as described in Japanese Unexamined Patent Application Publication No. 2012-146369, Toshiba Review Vol. 63, No. 2 (2008), pp. 28-31, and “SANJIGEN NAND FLASH, 2015 NEN NI HONKAKU RYOSAN E (Three-Dimensional NAND Flash, Full-Scale Mass Production in 2015)”, Nikkei Electronics, Sep. 16, 2013, pp. 81-90. 
         [0004]    By employing a three-dimensional structure in memory cells, the area of memories is substantially reduced. However, peripheral circuits, such as a decoder, are manufactured by using planar transistors, that is, by using a complementary metal-oxide semiconductor (CMOS) planar process, based on the related art, as described in Hirokazu Yoshizawa, CMOS OP AMP KAIRO JITSUMU SEKKEI NO KISO (CMOS OP Amplifier Circuit, Basis of Practical Design), CQ Publishing Co., Ltd., May 15, 2007, p. 23. Accordingly, it is expected that planar miniaturization based on the related art alone will not promote further increase in capacity and decrease in price. 
         [0005]    As a solution to address the above-described issue, a surrounding gate transistor (SGT) having a structure, in which the source, the gate, and the drain are disposed in a direction perpendicular to a substrate and the gate surrounds the island-shaped semiconductor layers, has been proposed, and a method for manufacturing SGTs, a CMOS inverter using SGTs, and a NAND circuit using SGTs have been disclosed (see Japanese Patent No. 5130596, Japanese Patent No. 5031809, and Japanese Patent No. 47566221, for example). 
         [0006]    NAND flash memory cells according to the related art using SGTs and having a three-dimensional structure are illustrated in  FIGS. 7 ,  8 A,  8 B, and  8 C. The details are described in Japanese Unexamined Patent Application Publication No. 2012-146369, Toshiba Review Vol. 63, No. 2 (2008), pp. 28-31, and “SANJIGEN NAND FLASH, 2015 NEN NI HONKAKU RYOSAN E (Three-Dimensional NAND Flash, Full-Scale Mass Production in 2015)”, Nikkei Electronics, Sep. 16, 2013, pp. 81-90, and therefore, a brief description will be given below. 
         [0007]      FIG. 7  is a diagram of an equivalent circuit including memory cell units of a NAND flash memory having a NAND configuration, which are arranged in a matrix form. M 0  to M 31  denote floating-type memory elements (transistors) that store charge on the floating gates or charge-trap-type memory elements (transistors) that store charge on nitride films, and are NAND-connected in series. STD denotes a drain selection transistor that is provided on the drain side in order to selectively connect the NAND-connected memory element group to a bit line, and STS denotes a source selection transistor that is provided on the source side in order to selectively connect the NAND-connected memory element group to a source line. 
         [0008]    A NAND group in which the drain selection transistor STD, the memory elements M 0  to M 31 , and the source selection transistor STS are connected in series is assumed to be one NAND unit (referred to as a NAND string) of a NAND flash memory. In  FIG. 7 , four NAND strings are provided to constitute a matrix. 
         [0009]    That is, a NAND string NAND(j, k) constituted by STD, M 0  to M 31 , and STS is disposed in a vertical stacking manner between a bit line BLk and a source line SL such that the bit line is positioned on an upper layer and the source line is positioned on a lower layer. Similarly, a NAND string NAND(j+1, k) is connected between the bit line BLk and the source line SL. A NAND string NAND(j, k+1) is connected between a bit line BL(k+1) and a source line SL, and a NAND string NAND(j+1, k+1) is connected between the bit line BL(k+1) and the source line SL. These NAND strings NAND(j, k), NAND(j+1, k), NAND(j, k+1), and NAND(j+1, k+1) constitute a matrix. 
         [0010]    To the gates of STD, M 0  to M 31 , and STS of NAND(j, k) and to the gates of STD, M 0  to M 31 , and STS of NAND(j, k+1), a drain selection signal SGDj, word line selection signals WL 0   j  to WL 31   j , and a source selection signal SGSj are input, respectively. 
         [0011]    To the gates of STD, M 0  to M 31 , and STS of NAND(j+1, k) and to the gates of STD, M 0  to M 31 , and STS of NAND(j+1, k+1), a drain selection signal SGD(j+1), word line selection signals WL 0 ( j+ 1) to WL 31 ( j+ 1), and a source selection signal SGS(j−1) are input, respectively. 
         [0012]      FIG. 8A  is a plan view of a layout in which the NAND flash memory cells in  FIG. 7  are formed by using SGTs.  FIG. 8B  is a cross-sectional view taken along cut line A-A′ in the plan view in  FIG. 8A , and  FIG. 8C  is a cross-sectional view taken along cut line B-B′ in the plan view in  FIG. 8A . 
         [0013]    In  FIGS. 8A ,  8 B, and  8 C, on an insulating film, such as a buried oxide (BOX) layer  1 M, formed on a substrate, a planar silicon layer  2 M is formed, and the planar silicon layer  2 M is formed of an n +  diffusion layer by impurity implantation or the like. Reference numeral  3 M denotes a silicide layer formed on the surface of the planar silicon layer  2 M. Reference numerals  4 M(j, k),  4 M(j+1, k),  4 M(j, k+1), and  4 M(j+1, k+1) denote p-type silicon pillars. Reference numeral  5 M denotes a gate insulating film for each of the n-channel metal-oxide semiconductor (hereinafter referred to as NMOS) transistors STD and the NMOS STS, which surrounds the silicon pillars  4 M(j, k),  4 M(j+1, k),  4 M(j, k+1), and  4 M(j+1, k+1). Reference numeral  51 M denotes a gate insulating film for each of the memory elements M 0  to M 31 , which surrounds the silicon pillars  4 M(j, k),  4 M(j+1, k),  4 M(j, k+1), and  4 M(j+1, k+1). Reference numerals  6 Msdj,  6 M 0   j  to  6 M 31   j ,  6 Mssj,  6 Msd(j+1),  6 M 0 ( j +1) to  6 M 31 ( j +1), and  6 Mss(j+1) denote gate electrodes that also serve as gate lines. On the top of each of the silicon pillars  4 M(j, k),  4 M(j+1, k),  4 M(j, k+1), and  4 M(j+1, k+1), an n +  diffusion layer  7 M is formed by impurity implantation or the like, and a metal line  16 Mk or a metal line  16 M(k+1) that serves as the bit line BLk or the bit line BL(k+1) is connected to the corresponding n +  diffusion layer  7 M. 
         [0014]    The NAND string NAND(j, k) is formed by using NAND connection in which the NMOS transistor STD, the memory elements M 0  to M 31 , and the NMOS transistor STS are connected in series such that the source of an element is connected to the drain of a subsequent element, the NMOS transistor STD being constituted by the silicon pillar  4 M(j, k), the gate insulating film  5 M, and the gate electrode  6 Msdj, the memory element M 0  being constituted by the silicon pillar  4 M(j, k), the gate insulating film  51 M, and the gate electrode  6 M 0   j , the memory element M 31  being constituted by the silicon pillar  4 M(j, k), the gate insulating film  51 M, and the gate electrode  6 M 31   j , the NMOS transistor STS being constituted by the silicon pillar  4 M(j, k), the gate insulating film  5 M, and the gate electrode  6 Mssj. The n +  diffusion layer  7 M on the top of the silicon pillar  4 Mj, which serves as the drain of the NMOS transistor STD is connected to the bit line BLk, which is the metal line  16 Mk, and the source of the NMOS transistor STS is connected to the lower diffusion layer  2 M, thereby being connected to the source line SL. 
         [0015]    The other NAND strings NAND(j+1, k), NAND(j, k+1), and NAND(j+1, k+1) also have similar configurations. 
         [0016]    The gate electrodes  6 Msdj,  6 M 0   j  to  6 M 31   j , and  6 Mssj, which also serve as gate lines, of the NMOS transistor STD, the memory elements M 0  to M 31 , and the NMOS transistor STS that constitute NAND(j, k) are laterally connected to the gate electrodes  6 Msdj,  6 M 0   j  to  6 M 31   j , and  6 Mssj, which also serve as gate lines, of the NMOS transistor STD, the memory elements M 0  to M 31 , and the NMOS transistor STS that constitute NAND(j, k+1), respectively on respective layers, in  FIG. 8A . 
         [0017]    Similarly, the gate electrodes  6 Msd(j+1),  6 M 0 ( j +1) to  6 M 31 ( j +1), and  6 Mss(j+1), which also serve as gate lines, of the NMOS transistor STD, the memory elements M 0  to M 31 , and the NMOS transistor STS that constitute NAND(j+1, k) are laterally connected to the gate electrodes  6 Msd(j+1),  6 M 0 ( j+ 1) to  6 M 31 ( j+ 1), and  6 Mss(j+1), which also serve as gate lines, of the NMOS transistor STD, the memory elements M 0  to M 31 , and the NMOS transistor STS that constitute NAND(j+1, k+1), respectively on respective layers, in  FIG. 8A . 
         [0018]    The bit line  16 Mk to which the NAND strings NAND(j, k) and NAND(j+1, k) are connected and the bit line  16 M(k+1) to which the NAND strings NAND(j, k+1) and NAND(j+1, k+1) are connected are disposed in the vertical direction extending in the up-down direction in  FIG. 8A . 
         [0019]    When an SGT-NAND flash memory, which is a three-dimensional NAND flash memory having the above-described configuration, is used, memory elements on 32 layers are vertically stacked in the NAND flash memory, and therefore, the degree of integration of memory elements is substantially increased and the price of the memory can be decreased. 
         [0020]    However, 34 signals SGDj, WL 0   j  to WL 31   j , and SGSj, that is, the gate electrodes  6 Msdj,  6 M 0   j  to  6 M 31   j , and  6 Mssj illustrated in  FIG. 8B  overlap in one location as illustrated in  FIG. 8A . Accordingly, a decoder circuit for selecting any of these 34 signals, which is formed by using a planar process, that is, by using a planar transistor in the related art, requires a substantial area. As a result, even if the area of memory elements is reduced, the area of a peripheral circuit, such as a decoder, increases, and therefore, the reduction is not effective in terms of the total area of the chip and the benefit specific to an SGT memory is not sufficiently gained, which has been an issue. 
         [0021]    On the other hand, in an inverter using SGTs illustrated in  FIGS. 9 ,  10 A, and  10 B, the p-channel metal-oxide semiconductor (hereinafter referred to as PMOS) transistor is completely isolated from the NMOS transistor in the structure, well isolation as in planar transistors is not needed, and a body terminal for supplying a potential to a well as in planar transistors is not needed because the silicon pillars serve as floating bodies. Accordingly, the inverter is characterized by a very compact layout (arrangement). 
         [0022]      FIG. 9  and  FIGS. 10A and 10B  are a circuit diagram and layout charts of an inverter that uses SGTs in the related art.  FIG. 9  is a circuit diagram of the inverter in which Qp denotes a PMOS transistor, Qn denotes an NMOS transistor, IN denotes an input signal, OUT denotes an output signal, Vcc denotes a supply voltage, and Vss denotes a reference voltage.  FIG. 10A  is a plan view of a layout in which the inverter in  FIG. 9  is formed by using SGTs, for example.  FIG. 10B  is a cross-sectional view taken along cut line A-A′ in the plan view in  FIG. 10A . 
         [0023]    In  FIGS. 10A and 10B , on an insulating film, such as a BOX layer  1 , formed on a substrate, planar silicon layers  2   p  and  2   n  are formed, and the planar silicon layers  2   p  and  2   n  are formed of a p +  diffusion layer and an n +  diffusion layer, respectively, by impurity implantation or the like. Reference numeral  3  denotes a silicide layer formed on the surface of the planar silicon layers  2   p  and  2   n , which connects the planar silicon layers  2   p  and  2   n  with each other. Reference numeral  4   n  denotes an n-type silicon pillar, and reference numeral  4   p  denotes a p-type silicon pillar. Reference numeral  5  denotes a gate insulating film that surrounds the silicon pillars  4   n  and  4   p . Reference numeral  6  denotes a gate electrode, and reference numeral  6   a  denotes a gate line. On the top of each of the silicon pillars  4   n  and  4   p , a p+ diffusion layer  7   p  and an n+ diffusion layer  7   n  are respectively formed by impurity implantation or the like. Reference numeral  8  denotes a silicon nitride film for protecting the gate insulating film  5  and the like. Reference numerals  9   p  and  9   n  denote silicide layers respectively connected to the p +  diffusion layer  7   p  and the n +  diffusion layer  7   n . Reference numeral  10   p  denotes a contact that connects the silicide layer  9   p  with a metal line  13   a , and reference numeral  10   n  denotes a contact that connects the silicide layer  9   n  with a metal line  13   b . Reference numeral  11  denotes a contact that connects the gate line  6   a  with a metal line  13   c.    
         [0024]    The PMOS transistor Qp is constituted by the silicon pillar  4   n , the lower diffusion layer  2   p , the upper diffusion layer  7   p , the gate insulating film  5 , and the gate electrode  6 , and the NMOS transistor Qn is constituted by the silicon pillar  4   p , the lower diffusion layer  2   n , the upper diffusion layer  7   n , the gate insulating film  5 , and the gate electrode  6 . The upper diffusion layers  7   p  and  7   n  serve as sources, and the lower diffusion layers  2   p  and  2   n  serve as drains. The supply voltage Vcc is supplied to the metal line  13   a , and the reference voltage Vss is supplied to the metal line  13   b . The input signal IN is connected to the metal line  13   c . The silicide layer  3  that connects the drain diffusion layer  2   p  of the PMOS transistor Qp with the drain diffusion layer  2   n  of the NMOS transistor Qn corresponds to the output OUT. 
         [0025]    In the inverter using SGTs illustrated in  FIGS. 9 ,  10 A, and  10 B, the PMOS transistor is completely isolated from the NMOS transistor in the structure, well isolation as in planar transistors is not needed, and a body terminal for supplying a potential to a well as in planar transistors is not needed because the silicon pillars serve as floating bodies. Accordingly, the inverter is characterized by a very compact layout (arrangement). 
       SUMMARY OF THE INVENTION 
       [0026]    The present invention provides a semiconductor device having a minimum area with a low price by configuring a decoder having a reduced area for an SGT-NAND flash memory, using the above-described feature of SGTs. 
         [0027]    A semiconductor device according to an aspect of the present invention is a semiconductor device including a decoder. The decoder includes a plurality of transistors arranged on a substrate, each of the plurality of transistors being formed by disposing a source, a drain, and a gate in layers in a direction perpendicular to the substrate. Each of the plurality of transistors includes a silicon pillar, an insulator that surrounds a side surface of the silicon pillar, a gate that surrounds the insulator, a source region that is disposed on the top or on the bottom of the silicon pillar, and a drain region that is disposed on the top or on the bottom of the silicon pillar, the drain region being disposed on an opposite side of the silicon pillar to the source region. The decoder includes at least a first selection signal line, n second selection signal lines, where n is a natural number, n MOS transistors, and n output lines. The n MOS transistors have gates that are connected to the first selection signal line. A k-th MOS transistor, where k=1 to n, has a source region and a drain region, one of the source region and the drain region being connected to any one of the n output lines. Another of the source region and the drain region of the k-th MOS transistor is disposed on the bottom of the silicon pillar, and is connected to a k-th selection signal line among the second selection signal lines, via a silicide layer that is disposed closer to the substrate than the silicon pillar. 
         [0028]    Preferably, the semiconductor device includes a plurality of the decoders, each of the plurality of the decoders including the n MOS transistors; and the other of the source region and the drain region of each k-th MOS transistor of each set of n MOS transistors that constitutes the plurality of the decoders is connected to a lower diffusion layer via the silicide layer. 
         [0029]    Preferably, the n output lines are formed as lines of a first wiring layer to an n-th wiring layer, respectively, and are disposed so as to extend in a first direction; and the lower diffusion layer to which the other of the source region and the drain region of each k-th MOS transistor is connected and the silicide layer that covers the lower diffusion layer are disposed so as to extend in a second direction perpendicular to the first direction. 
         [0030]    Preferably, the second selection signal lines are lines of a first metal wiring layer, which are disposed so as to extend in the second direction; and each of the lines of the first metal wiring layer is connected to the silicide layer that covers the lower diffusion layer via a contact. 
         [0031]    Preferably, the lines of the first metal wiring layer, which are disposed so as to extend in the second direction, are disposed below the lines formed in the first wiring layer to the n-th wiring layer, which are disposed so as to extend in the first direction. 
         [0032]    Preferably, the second selection signal lines are lines of a second metal wiring layer, which are disposed so as to extend in the second direction; each of the lines of the second metal wiring layer is connected to the silicide layer that covers the lower diffusion layer via a contact; and the lines of the second metal wiring layer are disposed above the lines of the first wiring layer to the n-th wiring layer. 
         [0033]    Preferably, the first wiring layer is made of a metal compound. 
         [0034]    A semiconductor device according to an aspect of the present invention is a semiconductor device including a decoder circuit. The decoder circuit includes a plurality of transistors arranged on a substrate, each of the plurality of transistors being formed by disposing a source, a drain, and a gate in layers in a direction perpendicular to the substrate. Each of the plurality of transistors includes a silicon pillar, an insulator that surrounds a side surface of the silicon pillar, a gate that surrounds the insulator, a source region that is disposed on the top or on the bottom of the silicon pillar, and a drain region that is disposed on the top or on the bottom of the silicon pillar, the drain region being disposed on an opposite side of the silicon pillar to the source region. The decoder circuit includes at least a first selection circuit, a first selection signal line output from the first selection circuit, n second selection signal lines, where n is a natural number, n MOS transistors, and n output lines. The n MOS transistors have gates that are connected to the first selection signal line. A k-th MOS transistor, where k=1 to n, has a source region and a drain region, one of the source region and the drain region being connected to any one of the n output lines. Another of the source region and the drain region of the k-th MOS transistor is disposed on the bottom of the silicon pillar, and is connected to a k-th selection signal line among the second selection signal lines, via a silicide layer that is disposed closer to the substrate than the silicon pillar. Each of the n output lines is connected to a gate electrode of a corresponding one of n memory elements. 
         [0035]    Preferably, the semiconductor device includes a plurality of the decoder circuits, each of the plurality of the decoder circuits including the n MOS transistors; and the other of the source region and the drain region of each k-th MOS transistor of each set of n MOS transistors that constitutes the plurality of the decoder circuits is connected to a lower diffusion layer via the silicide layer. 
         [0036]    Preferably, the n output lines are formed as lines of a first wiring layer to an n-th wiring layer, respectively, and are disposed so as to extend in a first direction; and the lower diffusion layer to which the other of the source region and the drain region of each k-th MOS transistor is connected and the silicide layer that covers the lower diffusion layer are disposed so as to extend in a second direction perpendicular to the first direction. 
         [0037]    Preferably, the second selection signal lines are lines of a first metal wiring layer, which are disposed so as to extend in the second direction; and each of the lines of the first metal wiring layer is connected to the silicide layer that covers the lower diffusion layer via a contact. 
         [0038]    Preferably, the lines formed in the first metal wiring layer are disposed in a layer below the lines formed in the first wiring layer to the n-th wiring layer. 
         [0039]    Preferably, the second selection signal lines are lines of a second metal wiring layer, which are disposed so as to extend in the second direction; each of the lines of the second metal wiring layer is connected to the silicide layer that covers the lower diffusion layer via a contact; and the lines of the second metal wiring layer are disposed above the lines of the first wiring layer to the n-th wiring layer. 
         [0040]    Preferably, the first wiring layer is made of a metal compound. 
         [0041]    A semiconductor device according to an aspect of the present invention is a semiconductor device including a decoder. The decoder includes a plurality of transistors arranged on a substrate, each of the plurality of transistors being formed by disposing a source, a drain, and a gate in layers in a direction perpendicular to the substrate. Each of the plurality of transistors includes a silicon pillar, an insulator that surrounds a side surface of the silicon pillar, a gate that surrounds the insulator, a source region that is disposed on the top or on the bottom of the silicon pillar, and a drain region that is disposed on the top or on the bottom of the silicon pillar, the drain region being disposed on an opposite side of the silicon pillar to the source region. The decoder includes a first selection circuit, a first selection signal line output from the first selection circuit, n second selection signal lines, where n is a natural number, n MOS transistors, n output lines, and a NAND-connected memory element group that includes n memory elements vertically stacked on the substrate, the n memory elements each including a drain, a source, and a gate electrode, the drain of a memory element being connected to the source of a subsequent memory element. The n MOS transistors are disposed in a column in a first direction, and have gates that are connected to the first selection signal line. A k-th MOS transistor, where k=1 to n, has a source region and a drain region, one of the source region and the drain region being connected to any one of the n output lines that are disposed so as to extend in the first direction. Another of the source region and the drain region of the k-th MOS transistor is disposed on the bottom of the silicon pillar, and is connected to a k-th selection signal line among the second selection signal lines that are disposed so as to extend in a second direction perpendicular to the first direction, via a silicide layer that is disposed closer to the substrate than the silicon pillar. Each of the n output lines is connected to the gate electrode of a corresponding one of the n memory elements in the memory element group. 
         [0042]    Preferably, the semiconductor device includes a plurality of the decoders; the plurality of the decoders are disposed side by side in the second direction; each of the plurality of the decoders further includes a second selection circuit that outputs the n second selection signal lines, where n is a natural number; the other of the source region and the drain region of a corresponding k-th MOS transistor among the plurality of the decoders is connected to a lower diffusion layer disposed on the bottom of the silicon pillar via the silicide layer, and is connected to the k-th selection signal line among the second selection signal lines; and a specified one memory element is selected from the memory element group by the first selection circuit and the second selection circuit. 
         [0043]    Preferably, the NAND-connected memory element group further includes a source line provided on a substrate side and a bit line provided on a top portion opposite the substrate side; and a first selection transistor, the n memory elements, and a second selection transistor are connected in this order between the bit line and the source line. 
         [0044]    Preferably, the second selection signal lines are lines of a first metal wiring layer, which are disposed so as to extend in the second direction; and each of the lines of the first metal wiring layer is connected to the silicide layer that covers a lower diffusion layer via a contact, and is disposed below the lines of the first wiring layer to the n-th wiring layer, which are disposed so as to extend in the first direction. 
         [0045]    Preferably, the second selection signal lines are lines of a second metal wiring layer, which are disposed so as to extend in the second direction; and each of the lines of the second metal wiring layer is connected to the silicide layer that covers a lower diffusion layer via a contact, and is disposed above the lines of the first wiring layer to the n-th wiring layer, which are disposed so as to extend in the first direction. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0046]      FIG. 1  is a diagram of an equivalent circuit in embodiments of the present invention; 
           [0047]      FIG. 2A  is a plan view of a decoder according to a first embodiment of the present invention; 
           [0048]      FIG. 2B  is a cross-sectional view of the decoder according to the first embodiment of the present invention; 
           [0049]      FIG. 2C  is a cross-sectional view of the decoder according to the first embodiment of the present invention; 
           [0050]      FIG. 2D  is a cross-sectional view of the decoder according to the first embodiment of the present invention; 
           [0051]      FIG. 2E  is a cross-sectional view of the decoder according to the first embodiment of the present invention; 
           [0052]      FIG. 2F  is a cross-sectional view of the decoder according to the first embodiment of the present invention; 
           [0053]      FIG. 3A  is a plan view of a decoder according to a second embodiment of the present invention; 
           [0054]      FIG. 3B  is a cross-sectional view of the decoder according to the second embodiment of the present invention; 
           [0055]      FIG. 3C  is a cross-sectional view of the decoder according to the second embodiment of the present invention; 
           [0056]      FIG. 3D  is a cross-sectional view of the decoder according to the second embodiment of the present invention; 
           [0057]      FIG. 3E  is a cross-sectional view of the decoder according to the second embodiment of the present invention; 
           [0058]      FIG. 3F  is a cross-sectional view of the decoder according to the second embodiment of the present invention; 
           [0059]      FIG. 4A  is a plan view of a decoder according to a third embodiment of the present invention; 
           [0060]      FIG. 4B  is a cross-sectional view of the decoder according to the third embodiment of the present invention; 
           [0061]      FIG. 4C  is a cross-sectional view of the decoder according to the third embodiment of the present invention; 
           [0062]      FIG. 4D  is a cross-sectional view of the decoder according to the third embodiment of the present invention; 
           [0063]      FIG. 4E  is a cross-sectional view of the decoder according to the third embodiment of the present invention; 
           [0064]      FIG. 4F  is a cross-sectional view of the decoder according to the third embodiment of the present invention; 
           [0065]      FIG. 5A  is a plan view of a decoder according to a fourth embodiment of the present invention; 
           [0066]      FIG. 5B  is a cross-sectional view of the decoder according to the fourth embodiment of the present invention; 
           [0067]      FIG. 6A  is a plan view of a decoder according to a fifth embodiment of the present invention; 
           [0068]      FIG. 6B  is a cross-sectional view of the decoder according to the fifth embodiment of the present invention; 
           [0069]      FIG. 7  is a diagram of an equivalent circuit of an SGT-NAND flash memory according to the related art; 
           [0070]      FIG. 8A  is a plan view of the SGT-NAND flash memory according to the related art; 
           [0071]      FIG. 8B  is a cross-sectional view of the SGT-NAND flash memory according to the related art; 
           [0072]      FIG. 8C  is a cross-sectional view of the SGT-NAND flash memory according to the related art; 
           [0073]      FIG. 9  is a diagram of an equivalent circuit of an inverter; 
           [0074]      FIG. 10A  is a plan view of the inverter according to the related art using SGTs; and 
           [0075]      FIG. 10B  is a cross-sectional view of the inverter according to the related art using SGTs. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0076]      FIG. 1  illustrates an equivalent circuit of a NAND string selection decoder  100 , which is employed in embodiments of the present invention and which is a decoder for an SGT-NAND flash memory. NAND(j, k) denotes the SGT-NAND string illustrated in  FIG. 7 . 
         [0077]    An NMOS transistor Tnsd is a selection transistor that connects a gate SGD of a drain selection transistor STD in the NAND string NAND(j, k) with a selection signal φsd. NMOS transistors Tn 0  to Tn 31  are selection transistors that connect gate signals WL 0  to WL 31  of memory elements M 0  to M 31  with selection signals φ 1  to φ 31 , respectively. An NMOS transistor Tnss is a selection transistor that connects a gate SGS of a source selection transistors STS with a selection signal φss. 
         [0078]    The NMOS transistors Tn 0  to Tn 31  constitute a memory element selection decoder  110  that selects any one of the memory elements M 0  to M 31 . The selection transistors Tnsd and Tnss and the NAND string NAND(j, k) in addition to the memory element selection decoder  110  constitute the NAND string selection decoder  100 . 
         [0079]    Reference numeral  200   j  denotes a row decoder that selects the NAND string selection decoder  100 , which receives an address signal ADDa and outputs a signal for selecting a NAND string to a booster  300   j . The booster  300   j  outputs a row selection signal RDj, the voltage of which has been boosted. The row selection signal RDj is input to the gates of the NMOS transistors Tnsd, Tn 0  to Tn 31 , and Tnss. A word line selector  400  receives an address signal ADDb, and outputs selection signals φsd, φ 0  to φ 31 , and φss. 
         [0080]    Although not illustrated, a plurality of NAND string selection decoders  100  are disposed in the up-down direction in  FIG. 1 , and the selection signals φsd, φ 0  to φ 31 , and φss, which are output from the word line selector  400 , are fed to each of the plurality of NAND string selection decoders  100 . 
         [0081]    That is, a NAND string selection decoder  100  is selected when the address signal ADDa from the row decoder  200   j  matches the address signal ADDb from the word line selector  400 . 
         [0082]    For example, when the address signal ADDa from the row decoder  200   j  matches the address signal ADDb and the row selection signal RDj is output from the booster  300   j , the NMOS transistors Tnsd, Tn 0  to Tn 31 , and Tnss are turned on, and the selection signals φsd, φ 0  to φ 31 , and φss are fed to the gates of the drain selection transistor STD, the memory elements M 0  to M 31 , and the source selection transistor STS, respectively. 
         [0083]    Here, a case of reading data of a memory element M 3  in a read mode will be discussed. A voltage of approximately 5 V is applied to the signals φsd and φss, the drain selection transistor STD and the source selection transistor STS are turned on, and the NAND string NAND(j, k) is connected to a bit line BLk and a source line SL. 
         [0084]    The memory element M 3  is selected, and therefore, the voltage of the selection signal φ 3  becomes substantially 0 V, and the voltage of the gate WL 3  of the memory element M 3  becomes substantially 0 V. On the other hand, a voltage of approximately 5 V is output to the selection signals φ 0  to φ 2  and φ 4  to φ 31  that are not selected. In this state, in a case where data of the memory element M 3  is in an erase state of “1”, the threshold of the memory element M 3  is negative, and therefore, the memory element M 3  is turned on even if the voltage of the gate WL 3  is 0 V, and a current flows from the bit line BLk to the source line SL. A sense amplifier, which is not illustrated, detects the current and determines that the data is “1”. 
         [0085]    On the other hand, in a state where data of the memory element  3  is “0”, the threshold of the memory element  3  is positive, and therefore, the memory element M 3  is turned off if the gate voltage is 0 V, no current flows from the bit line BLk to the source line SL, and the sense amplifier, which is not illustrated, determines that the data is “0”. 
         [0086]    Note that the NMOS transistors Tnsd, Tn 0 , . . . , Tn 31 , and Tnss operate as transfer gates, and therefore, the positions of the drains and the sources (orientations) are switched as appropriate in accordance with a direction in which the current flows. Here, for convenience sake, a state in a case where currents flow respectively from selection signal lines φsd, φ 0 , . . . , φ 31 , and φss to the gates SGD, WL 0 , . . . , WL 31 , and SGS in the NAND string is assumed, and the drains of the selection transistors Tnsd, Tn 0 , . . . , Tn 31 , and Tnss are specified to be connected to the selection signal lines φsd, φ 0 , . . . , φ 31 , and φss, and description will be given below. 
       First Embodiment 
       [0087]    A first embodiment is illustrated in  FIGS. 2A ,  2 B,  2 C,  2 D,  2 E, and  2 F.  FIG. 2A  is a plan view of a layout (arrangement) of a word line selection decoder according to this embodiment of the present invention.  FIG. 2B  is a cross-sectional view taken along cut line A-A′ in  FIG. 2A .  FIG. 2C  is a cross-sectional view taken along cut line B-B′ in  FIG. 2A .  FIG. 2D  is a cross-sectional view taken along cut line C-C′ in  FIG. 2A .  FIG. 2E  is a cross-sectional view taken along cut line D-D′ in  FIG. 2A .  FIG. 2F  is a cross-sectional view taken along cut line E-E′ in  FIG. 2A . An equivalent circuit in this embodiment is based on the memory element selection decoder  110  in  FIG. 1 . 
         [0088]      FIGS. 2A to 2F  illustrate a case where j=3 in  FIG. 1 . In  FIG. 2A , selection transistors Tn 00 , Tn 01 , Tn 02 , and Tn 03  are disposed in order in the lateral direction (first direction) in a row, on the top of  FIG. 2A . This row is defined as the first row. Gate electrodes  106  of the selection transistors Tn 00 , Tn 01 , Tn 02 , and Tn 03  are connected with each other by a gate line  106   a   0  that extends in the lateral direction, and a row selection signal RD 0  from the booster  300   j  illustrated in  FIG. 1  is input to the gate line  106   a   0 . 
         [0089]    Similarly, selection transistors Tn 10  to Tn 13  are disposed in order, as the second row below the first row, a gate line  106   a   1  is connected to the gate electrodes, and a row selection signal RD 1  is input to the gate line  106   a   1 . In the third row and in the fourth row, selection transistors Tn 20  to Tn 23  and selection transistors Tn 30  to Tn 33  are respectively disposed, a gate line  106   a   2  and a gate line  106   a   3  are connected to the corresponding gate electrodes respectively, and a row selection signal RD 2  and a row selection signal RD 3  are respectively input to the gate line  106   a   2  and the gate line  106   a   3 . 
         [0090]    In such arrangement, the selection transistors Tn 00 , Tn 10 , Tn 20 , and Tn 30  in the respective rows are longitudinally disposed in a column (second direction) on the left side in  FIG. 2A . This column is defined as the first column. Similarly, the selection transistors Tn 01 , Tn 11 , Tn 21 , and Tn 31  in the respective rows are disposed in the second column, the selection transistors Tn 02 , Tn 12 , Tn 22 , and Tn 32  in the respective rows are disposed in the third column, and the selection transistors Tn 03 , Tn 13 , Tn 23 , and Tn 33  in the respective rows are disposed in the fourth column. That is, the selection transistors are arranged in a matrix form. 
         [0091]    Although detailed description will be given below, in the first column, a selection signal line φ 0  is disposed so as to longitudinally extend by using a lower diffusion layer, and is connected to the lower diffusion layer, which serves as the drains of the selection transistors Tn 00 , Tn 10 , Tn 20 , and Tn 30  disposed in the respective rows, via a silicide layer. Similarly, in the second column, a selection signal line φ 1  is disposed so as to longitudinally extend by using a lower diffusion layer, and is connected to the lower diffusion layer, which serves as the drains of the selection transistors Tn 01 , Tn 11 , Tn 21 , and Tn 31  disposed in the respective rows, via a silicide layer. In the third column, a selection signal line φ 2  is disposed so as to longitudinally extend by using a lower diffusion layer, and is connected to the lower diffusion layer, which serves as the drains of the selection transistors Tn 02 , Tn 12 , Tn 22 , and Tn 32  disposed in the respective rows, via a silicide layer. In the fourth column, a selection signal line φ 3  is disposed so as to longitudinally extend by using a lower diffusion layer, and is connected to the lower diffusion layer, which serves as the drains of the selection transistors Tn 03 , Tn 13 , Tn 23 , and Tn 33  disposed in the respective rows, via a silicide layer. 
         [0092]    In the first row, lines  115   a   0  to  115   d   0  of the first to fourth metal compound wiring layers (wiring layers made of a metal compound, such as silicide) connected to memory elements, which are not illustrated, are overlap one another and are disposed so as to extend in the longitudinal and lateral directions. The line  115   a   0  is connected to the upper source of the selection transistor Tn 00 , the line  115   b   0  is connected to the upper source of the selection transistor Tn 01 , the line  115   c   0  is connected to the upper source of the selection transistor Tn 02 , and the line  115   d   0  is connected to the upper source of the selection transistor Tn 03 . 
         [0093]    Similarly, in the second row, lines  115   a   1  to  115   d   1  respectively formed in the first to fourth metal compound wiring layers are disposed. In the third row, lines  115   a   2  to  115   d   2  respectively formed in the first to fourth metal compound wiring layers are disposed. In the fourth row, lines  115   a   3  to  115   d   3  respectively formed in the first to fourth metal compound wiring layers are disposed. 
         [0094]    As described above, 16 selection transistors that constitute a decoder circuit for selecting the memory elements M 0  to M 3  of the NAND strings NAND(0, 0), NAND(1, k), NAND(2, k), and NAND(3, k), which are not illustrated, are efficiently arranged in a matrix form to thereby implement a row selection decoder having a reduced area. 
         [0095]    Note that, in  FIGS. 2A ,  2 B,  2 C,  2 D,  2 E, and  2 F, a portion having the same structure as the corresponding one in  FIGS. 10A and 10B  is denoted by a corresponding reference numeral in the one hundreds. 
         [0096]    In  FIGS. 2A ,  2 B,  2 C,  2 D,  2 E, and  2 F, planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd  are formed on an insulating film, such as a BOX layer  101 , formed on a substrate. The planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd  are respectively formed of n +  diffusion layers formed by impurity implantation or the like. Reference numeral  103  denotes a silicide layer formed on the surface of each of the planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd . Reference numerals  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33  each denote a p-type silicon pillar. Reference numeral  105  denotes a gate insulating film that surrounds the silicon pillars  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33 . Reference numeral  106  denotes the gate electrode. Reference numerals  106   a   0 ,  106   a   1 ,  106   a   2 , and  106   a   3  each denote the gate line. The gate insulating film  105  is also formed under the gate electrode  106  and the gate lines  106   a   0 ,  106   a   1 ,  106   a   2 , and  106   a   3 . 
         [0097]    On the top portions of the silicon pillars  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33 , n +  diffusion layers  107   n   00 ,  107   n   01 ,  107   n   02 ,  107   n   03 ,  107   n   10 ,  107   n   11 ,  107   n   12 ,  107   n   13 ,  107   n   20 ,  107   n   21 ,  107   n   22 ,  107   n   23 ,  107   n   30 ,  107   n   31 ,  107   n   32 , and  107   n   33  are respectively formed by impurity implantation or the like. Reference numeral  108  denotes a silicon-nitride film for protecting the gate insulating film  105 . Reference numerals  109   n   00 ,  109   n   01 ,  109   n   02 ,  109   n   03 ,  109   n   10 ,  109   n   11 ,  109   n   12 ,  109   n   13 ,  109   n   20 ,  109   n   21 ,  109   n   22 ,  109   n   23 ,  109   n   30 ,  109   n   31 ,  109   n   32 , and  109   n   33  denote silicide layers connected to the n +  diffusion layers  107   n   00 ,  107   n   01 ,  107   n   02 ,  107   n   03 ,  107   n   10 ,  107   n   11 ,  107   n   12 ,  107   n   13 ,  107   n   20 ,  107   n   21 ,  107   n   22 ,  107   n   23 ,  107   n   30 ,  107   n   31 ,  107   n   32 , and  107   n   33 , respectively. 
         [0098]    Reference numerals  110   n   00 ,  110   n   01 ,  110   n   02 ,  110   n   03 ,  110   n   10 ,  110   n   11 ,  110   n   12 ,  110   n   13 ,  110   n   20 ,  110   n   21 ,  110   n   22 ,  110   n   23 ,  110   n   30 ,  110   n   31 ,  110   n   32 , and  110   n   33  denote contacts. The contact  110   n   00  connects the silicide layer  109   n   00  with the line  115   a   0  of the first metal compound wiring layer. The contact  110   n   01  connects the silicide layer  109   n   01  with the line  115   b   0  of the second metal compound wiring layer. The contact  110   n   02  connects the silicide layer  109   n   02  with the line  115   c   0  of the third metal compound wiringmetal compound wiring layer. The contact  110   n   03  connects the silicide layer  109   n   03  with the line  115   d   0  of the fourth metal compound wiringmetal compound wiring layer. The contact  110   n   10  connects the silicide layer  109   n   10  with the line  115   a   1  of the first metal compound wiringmetal compound wiring layer. The contact  110   n   11  connects the silicide layer  109   n   11  with the line  115   b   1  of the second metal compound wiringmetal compound wiring layer. The contact  110   n   12  connects the silicide layer  109   n   12  with the line  115   c   1  of the third metal compound wiringmetal compound wiring layer. The contact  110   n   13  connects the silicide layer  109   n   13  with the line  115   d   1  of the fourth metal compound wiringmetal compound wiring layer. The contact  110   n   20  connects the silicide layer  109   n   20  with the line  115   a   2  of the first metal compound wiringmetal compound wiring layer. The contact  110   n   21  connects the silicide layer  109   n   21  with the line  115   b   2  of the second metal compound wiringmetal compound wiring layer. The contact  110   n   22  connects the silicide layer  109   n   22  with the line  115   c   2  of the third metal compound wiringmetal compound wiring layer. The contact  110   n   23  connects the silicide layer  109   n   23  with the line  115   d   2  of the fourth metal compound wiringmetal compound wiring layer. The contact  110   n   30  connects the silicide layer  109   n   30  with the line  115   a   3  of the first metal compound wiringmetal compound wiring layer. The contact  110   n   31  connects the silicide layer  109   n   31  with the line  115   b   3  of the second metal compound wiring layer. The contact  110   n   32  connects the silicide layer  109   n   32  with the line  115   c   3  of the third metal compound wiring layer. The contact  110   n   33  connects the silicide layer  109   n   33  with the line  115   d   3  of the fourth metal compound wiring layer. 
         [0099]    The silicon pillar  104   p   00 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   00 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 00 . The silicon pillar  104   p   01 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   01 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 01 . The silicon pillar  104   p   02 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   02 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 02 . The silicon pillar  104   p   03 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   03 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 03 . 
         [0100]    The silicon pillar  104   p   10 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   10 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 10 . The silicon pillar  104   p   11 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   11 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 11 . The silicon pillar  104   p   12 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   12 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 12 . The silicon pillar  104   p   13 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   13 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 13 . 
         [0101]    The silicon pillar  104   p   20 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   20 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 20 . The silicon pillar  104   p   21 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   21 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 21 . The silicon pillar  104   p   22 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   22 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 22 . The silicon pillar  104   p   23 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   23 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 23 . 
         [0102]    The silicon pillar  104   p   30 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   30 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 30 . The silicon pillar  104   p   31 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   31 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 31 . The silicon pillar  104   p   32 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   32 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 32 . The silicon pillar  104   p   33 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   33 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 33 . 
         [0103]    To the gate electrodes  106  of the NMOS transistors Tn 00 , Tn 01 , Tn 02 , and Tn 03 , the gate line  106   a   0  is connected. To the gate electrodes  106  of the NMOS transistors Tn 10 , Tn 11 , Tn 12 , and Tn 13 , the gate line  106   a   1  is connected. To the gate electrodes  106  of the NMOS transistors Tn 20 , Tn 21 , Tn 22 , and Tn 23 , the gate line  106   a   2  is connected. To the gate electrodes  106  of the NMOS transistors Tn 30 , Tn 31 , Tn 32 , and Tn 33 , the gate line  106   a   3  is connected. 
         [0104]    The lower diffusion layer  102   na  serves as a common drain of the NMOS transistors Tn 00 , Tn 10 , Tn 20 , and Tn 30  via the silicide layer  103 , and the selection signal φ 0  is fed to the lower diffusion layer  102   na.    
         [0105]    The lower diffusion layer  102   nb  serves as a common drain of the NMOS transistors Tn 01 , Tn 11 , Tn 21 , and Tn 31  via the silicide layer  103 , and the selection signal φ 1  is fed to the lower diffusion layer  102   nb.    
         [0106]    The lower diffusion layer  102   nc  serves as a common drain of the NMOS transistors Tn 02 , Tn 12 , Tn 22 , and Tn 32  via the silicide layer  103 , and the selection signal φ 2  is fed to the lower diffusion layer  102   nc.    
         [0107]    The lower diffusion layer  102   nd  serves as a common drain of the NMOS transistors Tn 03 , Tn 13 , Tn 23 , and Tn 33  via the silicide layer  103 , and the selection signal φ 3  is fed to the lower diffusion layer  102   nd.    
         [0108]    According to this embodiment, by using SGTs, a decoder having a reduced area, which operates as follows, can be provided. That is, the selection signals φ 0 , φ 1 , φ 2 , and φ 3  are respectively fed to the lower diffusion layers  102   na ,  102   nb ,  102   nc , and  102   nd  that extend in the longitudinal direction. Any one set is selected from among the sets of lines  115   a   0  to  115   d   0 ,  115   a   1  to  115   d   1 ,  115   a   2  to  115   d   2 , and  115   a   3  to  115   d   3 , which are in the first to fourth metal compound wiring layers respectively, in accordance with any one signal selected from among the selection signals RD 0  to RD 3  of the row decoder, which is not illustrated, via the selection transistors Tn 00  to Tn 33 , Tn 10  to Tn 13 , Tn 20  to Tn 23 , or Tn 30  to Tn 33 , which are arranged in a matrix form. 
       Second Embodiment 
       [0109]    A second embodiment is illustrated in  FIGS. 3A ,  3 B,  3 C,  3 D,  3 E, and  3 F.  FIG. 3A  is a plan view of a layout (arrangement) of a word line selection decoder according to this embodiment of the present invention.  FIG. 3B  is a cross-sectional view taken along cut line A-A′ in  FIG. 3A .  FIG. 3C  is a cross-sectional view taken along cut line B-B′ in  FIG. 3A .  FIG. 3D  is a cross-sectional view taken along cut line C-C′ in  FIG. 3A .  FIG. 3E  is a cross-sectional view taken along cut line D-D′ in  FIG. 3A .  FIG. 3F  is a cross-sectional view taken along cut line E-E′ in  FIG. 3A . An equivalent circuit in this embodiment is based on the memory element selection decoder  110  in  FIG. 1 . 
         [0110]      FIGS. 3A to 3F  are different from  FIGS. 2A to 2F  in that while only the lower diffusion layers  102   na ,  102   nb ,  102   nc , and  102   nd  are used in wiring of the selection signal lines φ 0  to φ 3  in  FIGS. 2A to 2F , wiring using a first metal wiring layer is employed, the first metal wiring layer being disposed in parallel with the lower diffusion layers, in  FIGS. 3A to 3F , and therefore, the wiring resistance is reduced. Such a configuration is employed by taking into consideration the fact that the resistance of the lower diffusion layers is relatively high, and therefore, the parasitic resistance increases to a level that requires attention as the wiring length becomes longer. 
         [0111]    In  FIGS. 3A ,  3 B,  3 C,  3 D,  3 E, and  3 F, lines  113   b ,  113   d ,  113   f , and  113   h  formed in the first metal wiring layer are provided below the lines  115   d   0  to  115   d   3  formed in the fourth metal compound wiring layer. The lines  113   b ,  113   d ,  113   f , and  113   h  are disposed so as to extend along the lower diffusion layers  102   na ,  102   nb ,  102   nc , and  102   nd  respectively, in the longitudinal direction (second direction) in  FIG. 3A , and are connected to the lower diffusion layers at fixed intervals via contacts and silicide layers. The selection signals φ 0  to φ 3  are respectively fed to the lines  113   b ,  113   d ,  113   f , and  113   h  in the first metal wiring layer, and therefore, the wiring resistance is reduced. 
         [0112]    Note that, in  FIGS. 3A ,  3 B,  3 C,  3 D,  3 E, and  3 F, a portion having the same structure as the corresponding one in  FIGS. 2A ,  2 B,  2 C,  2 D,  2 E, and  2 F is denoted by a corresponding reference numeral in the one hundreds. 
         [0113]    In  FIGS. 3A ,  3 B,  3 C,  3 D,  3 E, and  3 F, the planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd  are formed on an insulating film, such as the BOX layer  101 , formed on a substrate. The planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd  are respectively formed of n +  diffusion layers formed by impurity implantation or the like. Reference numeral  103  denotes a silicide layer formed on the surface of each of the planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd . Reference numerals  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33  each denote a p-type silicon pillar. Reference numeral  105  denotes a gate insulating film that surrounds the silicon pillars  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33 . Reference numeral  106  denotes a gate electrode. Reference numerals  106   a   0 ,  106   a   1 ,  106   a   2 , and  106   a   3  each denote a gate line. The gate insulating film  105  is also formed under the gate electrode  106  and the gate lines  106   a   0 ,  106   a   1 ,  106   a   2 , and  106   a   3 . 
         [0114]    On the top portions of the silicon pillars  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33 , the n +  diffusion layers  107   n   00 ,  107   n   01 ,  107   n   02 ,  107   n   03 ,  107   n   10 ,  107   n   11 ,  107   n   12 ,  107   n   13 ,  107   n   20 ,  107   n   21 ,  107   n   22 ,  107   n   23 ,  107   n   30 ,  107   n   31 ,  107   n   32 , and  107   n   33  are respectively formed by impurity implantation or the like. Reference numeral  108  denotes a silicon-nitride film for protecting the gate insulating film  105 . Reference numerals  109   n   00 ,  109   n   01 ,  109   n   02 ,  109   n   03 ,  109   n   10 ,  109   n   11 ,  109   n   12 ,  109   n   13 ,  109   n   20 ,  109   n   21 ,  109   n   22 ,  109   n   23 ,  109   n   30 ,  109   n   31 ,  109   n   32 , and  109   n   33  denote silicide layers connected to the n +  diffusion layers  107   n   00 ,  107   n   01 ,  107   n   02 ,  107   n   03 ,  107   n   10 ,  107   n   11 ,  107   n   12 ,  107   n   13 ,  107   n   20 ,  107   n   21 ,  107   n   22 ,  107   n   23 ,  107   n   30 ,  107   n   31 ,  107   n   32 , and  107   n   33 , respectively. 
         [0115]    Reference numerals  110   n   00 ,  110   n   01 ,  110   n   02 ,  110   n   03 ,  110   n   10 ,  110   n   11 ,  110   n   12 ,  110   n   13 ,  110   n   20 ,  110   n   21 ,  110   n   22 ,  110   n   23 ,  110   n   30 ,  110   n   31 ,  110   n   32 , and  110   n   33  denote contacts. The contact  110   n   00  connects the silicide layer  109   n   00  with the line  113   a   0  of the first metal wiring layer. The contact  110   n   01  connects the silicide layer  109   n   01  with the line  113   c   0  of the first metal wiring layer. The contact  110   n   02  connects the silicide layer  109   n   02  with the line  113   e   0  of the first metal wiring layer. The contact  110   n   03  connects the silicide layer  109   n   03  with the line  113   g   0  of the first metal wiring layer. The contact  110   n   10  connects the silicide layer  109   n   10  with the line  113   a   1  of the first metal wiring layer. The contact  110   n   11  connects the silicide layer  109   n   11  with the line  113   c   1  of the first metal wiring layer. The contact  110   n   12  connects the silicide layer  109   n   12  with the line  113   e   1  of the first metal wiring layer. The contact  110   n   13  connects the silicide layer  109   n   13  with the line  113   g   1  of the first metal wiring layer. The contact  110   n   20  connects the silicide layer  109   n   20  with the line  113   a   2  of the first metal wiring layer. The contact  110   n   21  connects the silicide layer  109   n   21  with the line  113   c   2  of the first metal wiring layer. The contact  110   n   22  connects the silicide layer  109   n   22  with the line  113   e   2  of the first metal wiring layer. The contact  110   n   23  connects the silicide layer  109   n   23  with the line  113   g   2  of the first metal wiring layer. The contact  110   n   30  connects the silicide layer  109   n   30  with the line  113   a   3  of the first metal wiring layer. The contact  110   n   31  connects the silicide layer  109   n   31  with the line  113   c   3  of the first metal wiring layer. The contact  110   n   32  connects the silicide layer  109   n   32  with the line  113   e   3  of the first metal wiring layer. The contact  110   n   33  connects the silicide layer  109   n   33  with the line  113   g   3  of the first metal wiring layer. Reference numerals  114   n   00 ,  114   n   01 ,  114   n   02 ,  114   n   03 ,  114   n   10 ,  114   n   11 ,  114   n   12 ,  114   n   13 ,  114   n   20 ,  114   n   21 ,  114   n   22 ,  114   n   23 ,  114   n   30 ,  114   n   31 ,  114   n   32 , and  114   n   33  denote contacts. The contact  114   n   00  connects the line  113   a   0  of the first metal wiring layer with the line  115   a   0  of the first metal compound wiring layer connected to a word line. The contact  114   n   01  connects the line  113   c   0  of the first metal wiring layer with the line  115   b   0  of the second metal compound wiring layer connected to a word line. The contact  114   n   02  connects the line  113   e   0  of the first metal wiring layer with the line  115   c   0  of the third metal compound wiring layer connected to a word line. The contact  114   n   03  connects the line  113   g   0  of the first metal wiring layer with the line  115   d   0  of the fourth metal compound wiring layer connected to a word line. The contact  114   n   10  connects the line  113   a   1  of the first metal wiring layer with the line  115   a   1  of the first metal compound wiring layer connected to a word line. The contact  114   n   11  connects the line  113   c   1  of the first metal wiring layer with the line  115   b   1  of the second metal compound wiring layer connected to a word line. The contact  114   n   12  connects the line  113   e   1  of the first metal wiring layer with the line  115   c   1  of the third metal compound wiring layer connected to a word line. The contact  114   n   13  connects the line  113   g   1  of the first metal wiring layer with the line  115   d   1  of the fourth metal compound wiring layer connected to a word line. The contact  114   n   20  connects the line  113   a   2  of the first metal wiring layer with the line  115   a   2  of the first metal compound wiring layer connected to a word line. The contact  114   n   21  connects the line  113   c   2  of the first metal wiring layer with the line  115   b   2  of the second metal compound wiring layer connected to a word line. The contact  114   n   22  connects the line  113   e   2  of the first metal wiring layer with the line  115   c   2  of the third metal compound wiring layer connected to a word line. 
         [0116]    The contact  114   n   23  connects the line  113   g   2  of the first metal wiring layer with the line  115   d   2  of the fourth metal compound wiring layer connected to a word line. The contact  114   n   30  connects the line  113   a   3  of the first metal wiring layer with the line  115   a   3  of the first metal compound wiring layer connected to a word line. The contact  114   n   31  connects the line  113   c   3  of the first metal wiring layer with the line  115   b   3  of the second metal compound wiring layer connected to a word line. The contact  114   n   32  connects the line  113   e   3  of the first metal wiring layer with the line  115   c   3  of the third metal compound wiring layer connected to a word line. The contact  114   n   33  connects the line  113   g   3  of the first metal wiring layer with the line  115   d   3  of the fourth metal compound wiring layer connected to a word line. 
         [0117]    Reference numerals  112   a   0 ,  112   a   1 ,  112   a   2 , and  112   a   3  denote contacts that connect the line  113   b  of the first metal wiring layer with the lower diffusion layer  102   na  via the silicide layer  103 . Reference numerals  112   b   0 ,  112   b   1 ,  112   b   2 , and  112   b   3  denote contacts that connect the line  113   d  of the first metal wiring layer with the lower diffusion layer  102   nb  via the silicide layer  103 . Reference numerals  112   c   0 ,  112   c   1 ,  112   c   2 , and  112   c   3  denote contacts that connect the line  113   f  of the first metal wiring layer with the lower diffusion layer  102   nc  via the silicide layer  103 . Reference numerals  112   d   0 ,  112   d   1 ,  112   d   2 , and  112   d   3  denote contacts that connect the line  113   h  of the first metal wiring layer with the lower diffusion layer  102   nd  via the silicide layer  103 . 
         [0118]    The silicon pillar  104   p   00 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   00 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 00 . The silicon pillar  104   p   01 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   01 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 01 . The silicon pillar  104   p   02 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   02 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 02 . The silicon pillar  104   p   03 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   03 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 03 . 
         [0119]    The silicon pillar  104   p   10 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   10 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 10 . The silicon pillar  104   p   11 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   11 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 11 . The silicon pillar  104   p   12 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   12 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 12 . The silicon pillar  104   p   13 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   13 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 13 . 
         [0120]    The silicon pillar  104   p   20 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   20 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 20 . The silicon pillar  104   p   21 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   21 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 21 . The silicon pillar  104   p   22 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   22 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 22 . The silicon pillar  104   p   23 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   23 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 23 . 
         [0121]    The silicon pillar  104   p   30 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   30 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 30 . The silicon pillar  104   p   31 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   31 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 31 . The silicon pillar  104   p   32 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   32 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 32 . The silicon pillar  104   p   33 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   33 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 33 . 
         [0122]    To the gate electrodes  106  of the NMOS transistors Tn 00 , Tn 01 , Tn 02 , and Tn 03 , the gate line  106   a   0  is connected. To the gate electrodes  106  of the NMOS transistors Tn 10 , Tn 11 , Tn 12 , and Tn 13 , the gate line  106   a   1  is connected. To the gate electrodes  106  of the NMOS transistors Tn 20 , Tn 21 , Tn 22 , and Tn 23 , the gate line  106   a   2  is connected. To the gate electrodes  106  of the NMOS transistors Tn 30 , Tn 31 , Tn 32 , and Tn 33 , the gate line  106   a   3  is connected. 
         [0123]    The lower diffusion layer  102   na  serves as a common drain of the NMOS transistors Tn 00 , Tn 10 , Tn 20 , and Tn 30  via the silicide layer  103 . The lower diffusion layer  102   na  is connected to the line  113   b  of the first metal wiring layer via the contacts  112   a   0 ,  112   a   1 ,  112   a   2 , and  112   a   3 , and the selection signal φ 0  is fed to the line  113   b.    
         [0124]    The lower diffusion layer  102   nb  serves as a common drain of the NMOS transistors Tn 01 , Tn 11 , Tn 21 , and Tn 31  via the silicide layer  103 . The lower diffusion layer  102   nb  is connected to the line  113   d  of the first metal wiring layer via the contacts  112   b   0 ,  112   b   1 ,  112   b   2 , and  112   b   3 , and the selection signal φ 1  is fed to the line  113   d.    
         [0125]    The lower diffusion layer  102   nc  serves as a common drain of the NMOS transistors Tn 02 , Tn 12 , Tn 22 , and Tn 32  via the silicide layer  103 . The lower diffusion layer  102   nc  is connected to the line  113   f  of the first metal wiring layer via the contacts  112   c   0 ,  112   c   1 ,  112   c   2 , and  112   c   3 , and the selection signal φ 2  is fed to the line  113   f.    
         [0126]    The lower diffusion layer  102   nd  serves as a common drain of the NMOS transistors Tn 03 , Tn 13 , Tn 23 , and Tn 33  via the silicide layer  103 . The lower diffusion layer  102   nd  is connected to the line  113   h  of the first metal wiring layer via the contacts  112   d   0 ,  112   d   1 ,  112   d   2 , and  112   d   3 , and the selection signal φ 3  is fed to the line  113   h.    
         [0127]    According to this embodiment, by using SGTs, a decoder having a reduced area, which operates as follows, can be provided. That is, the selection signals φ 0 , φ 1 , φ 2 , and φ 3  are fed to the lower diffusion layers  102   na ,  102   nb ,  102   nc , and  102   nd  that extend in the longitudinal direction via the contacts  112   a   0  to  112   a   3 , the contacts  112   b   0  to  112   b   3 , the contacts  112   c   0  to  112   c   3 , and the contacts  112   d   0  to  112   d   3  respectively from the lines  113   b ,  113   d ,  113   f , and  113   h  formed in the first metal wiring layer, which are also disposed so as to extend in the longitudinal direction. Any one set is selected from among the sets of lines  115   a   0  to  115   d   0 ,  115   a   1  to  115   d   1 ,  115   a   2  to  115   d   2 , and  115   a   3  to  115   d   3  that are connected to word lines of memory elements, which are not illustrated, in accordance with any one signal selected from among the selection signals RD 0  to RD 3  of the row decoder, which is not illustrated, via the selection transistors Tn 00  to Tn 03 , Tn 10  to Tn 13 , Tn 20  to Tn 23 , or Tn 30  to Tn 33  that are arranged in a matrix form. 
         [0128]    Note that the lines  113   a   0 ,  113   c   0 ,  113   e   0 ,  113   g   0 ,  113   a   1 ,  113   c   1 ,  113   e   1 ,  113   g   1 ,  113   a   2 ,  113   c   2 ,  113   e   2 ,  113   g   2 ,  113   a   3 ,  113   c   3 ,  113   e   3 , and  113   g   3  of the first metal wiring layer may be omitted, the line  113   a   0  being disposed between the upper source region of the selection transistor Tn 00  and the line  115   a   0  of the first metal compound wiring layer, the line  113   c   0  being disposed between the upper source region of the selection transistor Tn 01  and the line  115   b   0  of the second metal compound wiring layer, the line  113   e   0  being disposed between the upper source region of the selection transistor Tn 02  and the line  115   c   0  of the third metal compound wiring layer, the line  113   g   0  being disposed between the upper source region of the selection transistor Tn 03  and the line  115   d   0  of the fourth metal compound wiring layer, the line  113   a   1  being disposed between the upper source region of the selection transistor Tn 10  and the line  115   a   1  of the first metal compound wiring layer, the line  113   c   1  being disposed between the upper source region of the selection transistor Tn 11  and the line  115   b   1  of the second metal compound wiring layer, the line  113   e   1  being disposed between the upper source region of the selection transistor Tn 12  and the line  115   c   1  of the third metal compound wiring layer, the line  113   g   1  being disposed between the upper source region of the selection transistor Tn 13  and the line  115   d   1  of the fourth metal compound wiring layer, the line  113   a   2  being disposed between the upper source region of the selection transistor Tn 20  and the line  115   a   2  of the first metal compound wiring layer, the line  113   c   2  being disposed between the upper source region of the selection transistor Tn 21  and the line  115   b   2  of the second metal compound wiring layer, the line  113   e   2  being disposed between the upper source region of the selection transistor Tn 22  and the line  115   c   2  of the third metal compound wiring layer, the line  113   g   2  being disposed between the upper source region of the selection transistor Tn 23  and the line  115   d   2  of the fourth metal compound wiring layer, the line  113   a   3  being disposed between the upper source region of the selection transistor Tn 30  and the line  115   a   3  of the first metal compound wiring layer, the line  113   c   3  being disposed between the upper source region of the selection transistor Tn 31  and the line  115   b   3  of the second metal compound wiring layer, the line  113   e   3  being disposed between the upper source region of the selection transistor Tn 32  and the line  115   c   3  of the third metal compound wiring layer, the line  113   g   3  being disposed between the upper source region of the selection transistor Tn 33  and the line  115   d   3  of the fourth metal compound wiring layer. In this embodiment, the lines  113   a   0 ,  113   c   0 ,  113   e   0 ,  113   g   0 ,  113   a   1 ,  113   c   1 ,  113   e   1 ,  113   g   1 ,  113   a   2 ,  113   c   2 ,  113   e   2 ,  113   g   2 ,  113   a   3 ,  113   c   3 ,  113   e   3 , and  113   g   3  of the first metal wiring layer are disposed in order to separate a process of manufacturing portions below the first metal wiring layer  113  and a process of manufacturing portions disposed above the first metal wiring layer  113 , that is, the contacts  114  and subsequent portions. 
         [0129]    That is, a process of manufacturing portions up to the first metal wiring layer  113  including the selection transistors Tn 00  to Tn 03 , Tn 10  to Tn 13 , Tn 20  to Tn 23 , and Tn 30  to Tn 33  can be performed simultaneously with a process of manufacturing a logic circuit or the like to be disposed in other regions, which is not illustrated, thereby reducing an extra manufacturing process. 
       Third Embodiment 
       [0130]    A third embodiment is illustrated in  FIGS. 4A ,  4 B,  4 C,  4 D,  4 E, and  4 F.  FIG. 4A  is a plan view of a layout (arrangement) of a word line selection decoder according to this embodiment of the present invention.  FIG. 4B  is a cross-sectional view taken along cut line A-A′ in  FIG. 4A .  FIG. 4C  is a cross-sectional view taken along cut line B-B′ in  FIG. 4A .  FIG. 4D  is a cross-sectional view taken along cut line C-C′ in  FIG. 4A .  FIG. 4E  is a cross-sectional view taken along cut line D-D′ in  FIG. 4A .  FIG. 4F  is a cross-sectional view taken along cut line E-E′ in  FIG. 4A . An equivalent circuit in this embodiment is based on the memory element selection decoder  110  in  FIG. 1 . 
         [0131]      FIGS. 4A to 4F  are different from  FIGS. 3A to 3F  in that while the lines  113   b ,  113   d ,  113   f , and  113   h  of the first metal wiring layer are used in wiring of the selection signal lines φ 0  to φ 3  in  FIGS. 3A to 3F , lines  116   a ,  116   b ,  116   c , and  116   d  of the second metal wiring layer are used in wiring of the selection signal lines φ 0  to φ 3  in this embodiment. 
         [0132]    While the lines  113   b ,  113   d ,  113   f , and  113   h  of the first metal wiring layer are disposed in a region below the fourth metal compound wiring layer, the lines  116   a ,  116   b ,  116   c , and  116   d  of the second metal wiring layer are disposed in a region above the first metal compound wiring layer. 
         [0133]    Such a configuration is employed in order to use the same metal wiring layer in which the bit line BLk of the SGT-NAND string not illustrated are formed, which will be described below. 
         [0134]    In  FIGS. 4A ,  4 B,  4 C,  4 D,  4 E, and  4 F, the lines  116   a ,  116   b ,  116   c , and  116   d  formed in the second metal wiring layer are provided above the lines  115   a   0  to  115   a   3  formed in the first metal compound wiring layer. The lines  116   a ,  116   b ,  116   c , and  116   d  are disposed so as to extend along the lower diffusion layers  102   na ,  102   nb ,  102   nc , and  102   nd  respectively, in the longitudinal direction (second direction) in  FIG. 4A , and are connected to the lower diffusion layers at fixed intervals via contacts and silicide layers. The selection signals φ 0  to φ 3  are respectively fed to the lines  116   a ,  116   b ,  116   c , and  116   d  of the second metal wiring layer, and therefore, the wiring resistance is reduced. 
         [0135]    Note that, in  FIGS. 4A ,  4 B,  4 C,  4 D,  4 E, and  4 F, a portion having the same structure as the corresponding one in  FIGS. 3A ,  3 B,  3 C,  3 D,  3 E, and  3 F is denoted by a corresponding reference numeral in the one hundreds. 
         [0136]    In  FIGS. 4A ,  4 B,  4 C,  4 D,  4 E, and  4 F, the planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd  are formed on an insulating film, such as the BOX layer  101 , formed on a substrate. The planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd  are respectively formed of n +  diffusion layers formed by impurity implantation or the like. Reference numeral  103  denotes a silicide layer formed on the surface of each of the planar silicon layers  102   na ,  102   nb ,  102   nc , and  102   nd . Reference numerals  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33  each denote a p-type silicon pillar. Reference numeral  105  denotes a gate insulating film that surrounds the silicon pillars  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33 . Reference numeral  106  denotes a gate electrode. Reference numerals  106   a   0 ,  106   a   1 ,  106   a   2 , and  106   a   3  each denote a gate line. The gate insulating film  105  is also formed under the gate electrode  106  and the gate lines  106   a   0 ,  106   a   1 ,  106   a   2 , and  106   a   3 . 
         [0137]    On the top portions of the silicon pillars  104   p   00 ,  104   p   01 ,  104   p   02 ,  104   p   03 ,  104   p   10 ,  104   p   11 ,  104   p   12 ,  104   p   13 ,  104   p   20 ,  104   p   21 ,  104   p   22 ,  104   p   23 ,  104   p   30 ,  104   p   31 ,  104   p   32 , and  104   p   33 , the n +  diffusion layers  107   n   00 ,  107   n   01 ,  107   n   02 ,  107   n   03 ,  107   n   10 ,  107   n   11 ,  107   n   12 ,  107   n   13 ,  107   n   20 ,  107   n   21 ,  107   n   22 ,  107   n   23 ,  107   n   30 ,  107   n   31 ,  107   n   32 , and  107   n   33  are respectively formed by impurity implantation or the like. Reference numeral  108  denotes a silicon-nitride film for protecting the gate insulating film  105 . Reference numerals  109   n   00 ,  109   n   01 ,  109   n   02 ,  109   n   03 ,  109   n   10 ,  109   n   11 ,  109   n   12 ,  109   n   13 ,  109   n   20 ,  109   n   21 ,  109   n   22 ,  109   n   23 ,  109   n   30 ,  109   n   31 ,  109   n   32 , and  109   n   33  denote silicide layers connected to the n +  diffusion layers  107   n   00 ,  107   n   01 ,  107   n   02 ,  107   n   03 ,  107   n   10 ,  107   n   11 ,  107   n   12 ,  107   n   13 ,  107   n   20 ,  107   n   21 ,  107   n   22 ,  107   n   23 ,  107   n   30 ,  107   n   31 ,  107   n   32 , and  107   n   33 , respectively. 
         [0138]    Reference numerals  110   n   00 ,  110   n   01 ,  110   n   02 ,  110   n   03 ,  110   n   10 ,  110   n   11 ,  110   n   12 ,  110   n   13 ,  110   n   20 ,  110   n   21 ,  110   n   22 ,  110   n   23 ,  110   n   30 ,  110   n   31 ,  110   n   32 , and  110   n   33  denote contacts. The contact  110   n   00  connects the silicide layer  109   n   00  with the line  115   a   0  of the first metal compound wiring layer connected to a word line. The contact  110   n   01  connects the silicide layer  109   n   01  with the line  115   b   0  of the second metal compound wiring layer connected to a word line. The contact  110   n   02  connects the silicide layer  109   n   02  with the line  115   c   0  of the third metal compound wiring layer connected to a word line. The contact  110   n   03  connects the silicide layer  109   n   03  with the line  115   d   0  of the fourth metal compound wiring layer connected to a word line. The contact  110   n   10  connects the silicide layer  109   n   10  with the line  115   a   1  of the first metal compound wiring layer connected to a word line. The contact  110   n   11  connects the silicide layer  109   n   11  with the line  115   b   1  of the second metal compound wiring layer connected to a word line. The contact  110   n   12  connects the silicide layer  109   n   12  with the line  115   c   1  of the third metal compound wiring layer connected to a word line. The contact  110   n   13  connects the silicide layer  109   n   13  with the line  115   d   1  of the fourth metal compound wiring layer connected to a word line. The contact  110   n   20  connects the silicide layer  109   n   20  with the line  115   a   2  of the first metal compound wiring layer connected to a word line. The contact  110   n   21  connects the silicide layer  109   n   21  with the line  115   b   2  of the second metal compound wiring layer connected to a word line. The contact  110   n   22  connects the silicide layer  109   n   22  with the line  115   c   2  of the third metal compound wiring layer connected to a word line. The contact  110   n   23  connects the silicide layer  109   n   23  with the line  115   d   2  of the fourth metal compound wiring layer connected to a word line. The contact  110   n   30  connects the silicide layer  109   n   30  with the line  115   a   3  of the first metal compound wiring layer connected to a word line. The contact  110   n   31  connects the silicide layer  109   n   31  with the line  115   b   3  of the second metal compound wiring layer connected to a word line. The contact  110   n   32  connects the silicide layer  109   n   32  with the line  115   c   3  of the third metal compound wiring layer connected to a word line. The contact  110   n   33  connects the silicide layer  109   n   33  with the line  115   d   3  of the fourth metal compound wiring layer connected to a word line. 
         [0139]    Reference numerals  112   a   0 ,  112   a   1 ,  112   a   2 , and  112   a   3  denote contacts that connect the line  116   a  of the second metal wiring layer with the lower diffusion layer  102   na  via the silicide layer  103 . Reference numerals  112   b   0 ,  112   b   1 ,  112   b   2 , and  112   b   3  denote contacts that connect the line  116   b  of the second metal wiring layer with the lower diffusion layer  102   nb  via the silicide layer  103 . Reference numerals  112   c   0 ,  112   c   1 ,  112   c   2 , and  112   c   3  denote contacts that connect the line  116   c  of the second metal wiring layer with the lower diffusion layer  102   nc  via the silicide layer  103 . Reference numerals  112   d   0 ,  112   d   1 ,  112   d   2 , and  112   d   3  denote contacts that connect the line  116   d  of the second metal wiring layer with the lower diffusion layer  102   nd  via the silicide layer  103 . 
         [0140]    The silicon pillar  104   p   00 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   00 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 00 . The silicon pillar  104   p   01 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   01 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 01 . The silicon pillar  104   p   02 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   02 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 02 . The silicon pillar  104   p   03 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   03 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 03 . 
         [0141]    The silicon pillar  104   p   10 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   10 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 10 . The silicon pillar  104   p   11 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   11 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 11 . The silicon pillar  104   p   12 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   12 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 12 . The silicon pillar  104   p   13 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   13 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 13 . 
         [0142]    The silicon pillar  104   p   20 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   20 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 20 . The silicon pillar  104   p   21 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   21 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 21 . The silicon pillar  104   p   22 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   22 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 22 . The silicon pillar  104   p   23 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   23 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 23 . 
         [0143]    The silicon pillar  104   p   30 , the lower diffusion layer  102   na , the upper diffusion layer  107   n   30 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 30 . The silicon pillar  104   p   31 , the lower diffusion layer  102   nb , the upper diffusion layer  107   n   31 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 31 . The silicon pillar  104   p   32 , the lower diffusion layer  102   nc , the upper diffusion layer  107   n   32 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 32 . The silicon pillar  104   p   33 , the lower diffusion layer  102   nd , the upper diffusion layer  107   n   33 , the gate insulating film  105 , and the gate electrode  106  constitute the NMOS transistor Tn 33 . 
         [0144]    To the gate electrodes  106  of the NMOS transistors Tn 00 , Tn 01 , Tn 02 , and Tn 03 , the gate line  106   a   0  is connected. To the gate electrodes  106  of the NMOS transistors Tn 10 , Tn 11 , Tn 12 , and Tn 13 , the gate line  106   a   1  is connected. To the gate electrodes  106  of the NMOS transistors Tn 20 , Tn 21 , Tn 22 , and Tn 23 , the gate line  106   a   2  is connected. To the gate electrodes  106  of the NMOS transistors Tn 30 , Tn 31 , Tn 32 , and Tn 33 , the gate line  106   a   3  is connected. 
         [0145]    The lower diffusion layer  102   na  serves as a common drain of the NMOS transistors Tn 00 , Tn 10 , Tn 20 , and Tn 30  via the silicide layer  103 . The lower diffusion layer  102   na  is connected to the line  116   a  of the second metal wiring layer via the contacts  112   a   0 ,  112   a   1 ,  112   a   2 , and  112   a   3 , and the selection signal φ 0  is fed to the line  116   a.    
         [0146]    The lower diffusion layer  102   nb  serves as a common drain of the NMOS transistors Tn 01 , Tn 11 , Tn 21 , and Tn 31  via the silicide layer  103 . The lower diffusion layer  102   nb  is connected to the line  116   b  of the second metal wiring layer via the contacts  112   b   0 ,  112   b   1 ,  112   b   2 , and  112   b   3 , and the selection signal φ 1  is fed to the line  116   b.    
         [0147]    The lower diffusion layer  102   nc  serves as a common drain of the NMOS transistors Tn 02 , Tn 12 , Tn 22 , and Tn 32  via the silicide layer  103 . The lower diffusion layer  102   nc  is connected to the line  116   c  of the second metal wiring layer via the contacts  112   c   0 ,  112   c   1 ,  112   c   2 , and  112   c   3 , and the selection signal φ 2  is fed to the line  116   c.    
         [0148]    The lower diffusion layer  102   nd  serves as a common drain of the NMOS transistors Tn 03 , Tn 13 , Tn 23 , and Tn 33  via the silicide layer  103 . The lower diffusion layer  102   nd  is connected to the line  116   d  of the second metal wiring layer via the contacts  112   d   0 ,  112   d   1 ,  112   d   2 , and  112   d   3 , and the selection signal φ 3  is fed to the line  116   d.    
         [0149]    According to this embodiment, by using SGTs, a decoder having a reduced area, which operates as follows, can be provided. That is, the selection signals φ 0 , φ 1 , φ 2 , and φ 3  are fed to the lower diffusion layers  102   na ,  102   nb ,  102   nc , and  102   nd  that extend in the longitudinal direction via the contacts  112   a   0  to  112   a   3 , the contacts  112   b   0  to  112   b   3 , the contacts  112   c   0  to  112   c   3 , and the contacts  112   d   0  to  112   d   3  respectively from the lines  116   a ,  116   b ,  116   c , and  116   d  of the second metal wiring layer, which are also disposed so as to extend in the longitudinal direction. Any one set is selected from among the sets of lines  115   a   0  to  115   d   0 ,  115   a   1  to  115   d   1 ,  115   a   2  to  115   d   2 , and  115   a   3  to  115   d   3  that are connected to word lines of memory elements, which are not illustrated, in accordance with any one signal selected from among the selection signals RD 0  to RD 3  of the row decoder, which is not illustrated, via the selection transistors Tn 00  to Tn 03 , Tn 10  to Tn 13 , Tn 20  to Tn 23 , or Tn 30  to Tn 33  that are arranged in a matrix form. 
         [0150]    Furthermore, the lines  116   a ,  116   b ,  116   c , and  116   d  formed in the second metal wiring layer for feeding selection signals are formed by using the same wiring layer in which the bit line of memory cells, which are not illustrated, is formed to thereby simplify the manufacturing process. 
       Fourth Embodiment 
       [0151]    A fourth embodiment is illustrated in  FIGS. 5A and 5B .  FIG. 5A  is a plan view of a layout (arrangement) of a word line selection decoder according to this embodiment of the present invention.  FIG. 5B  is a cross-sectional view taken along cut line A-A′ in  FIG. 5A . An equivalent circuit in this embodiment is based on the NAND string selection decoder  100  in  FIG. 1 . In  FIGS. 5A and 5B , BL 110   b  illustrated in the second embodiment ( FIGS. 3A to 3F ) is employed as the memory element selection decoder  110 . 
         [0152]    Note that cross-sectional views taken along the longitudinal direction in  FIG. 5A  are the same as  FIGS. 3D ,  3 E, and  3 F, which are cross-sectional views taken along the longitudinal direction in  FIG. 3A , and therefore, the cross-sectional views taken along the longitudinal direction in  FIG. 5A  will be omitted here. 
         [0153]      FIGS. 5A and 5B  illustrate a configuration that includes SGT-NAND strings as illustrated in the NAND string selection decoder  100  in  FIG. 1 . That is, eight NAND strings NAND(j, k) (j=0 to 3, k=0 and 1) are arranged in a matrix form, and each NAND string NAND(j, k) includes the drain selection transistor STD, the memory elements M 0  to M 31 , and the source selection transistor STS, that is, 34 elements in total, which are vertically stacked and disposed in order in series. 
         [0154]    In  FIG. 5A , NAND(0, 0) and NAND(0, 1) are disposed in the top row laterally from the left side. The gate electrodes of the drain selection transistor STD, the memory elements M 0  to M 31 , and the source selection transistor STS, that is, total of 34 elements, which are connected in series, of each of NAND(0, 0) and NAND(0, 1) are connected as follows. That is, the gate electrodes of the drain selection transistors STD of NAND(0, 0) and NAND(0, 1) are connected with each other by a gate line  206 Msd that extends in the lateral direction (the first direction, also referred to as the row direction) in  FIG. 5A . The gate electrodes of the memory elements M 0  to M 31  of NAND(0, 0) and NAND(0, 1) are connected with each other by gate lines  206 M 0  to  206 M 31  that extend in the lateral direction, respectively. The gate electrodes of the source selection transistors STS of NAND(0, 0) and NAND(0, 1) are connected with each other by a gate line  206 Mss that extends in the lateral direction. 
         [0155]    Similarly, NAND(1, 0) and NAND(1, 1) are disposed in the second row laterally from the left side. NAND(2, 0) and NAND(2, 1) are disposed in the third row, and NAND(3, 0) and NAND(3, 1) are disposed in the fourth row. 
         [0156]    The drains of the drain selection transistors STD of NAND(0, 0), NAND(1, 0), NAND(2, 0), and NAND(3, 0) are connected to a bit line BL 0  that is disposed so as to extend in the longitudinal direction (second direction) in  FIG. 5A . The drains of the drain selection transistors STD of NAND(0, 1), NAND(1, 1), NAND(2, 1), and NAND(3, 1) are connected to a bit line BL 1  that is disposed so as to extend in the longitudinal direction (second direction). 
         [0157]    The sources of the source selection transistors STS of NAND(0, 0), NAND(1, 0), NAND(2, 0), NAND(3, 0), NAND(0, 1), NAND(1, 1), NAND(2, 1), and NAND(3, 1) are all connected to a lower diffusion layer  202 M that serves as a source line. 
         [0158]    Note that, in  FIGS. 5A and 5B , a portion having the same structure as the corresponding one in  FIGS. 3A ,  3 B,  3 C,  3 D,  3 E, and  3 F is denoted by a corresponding reference numeral in the two hundreds. 
         [0159]    As illustrated in  FIG. 5B , contacts  214   a ,  214   b ,  214   c ,  214   d , and  214   e  are newly provided for connection. The contact  214   a  is provided in order to connect a first metal compound wiring layer  215   a  with the gate line  206 Msd for the drain selection transistors STD of the NAND strings NAND(0, 0) and NAND(0, 1). The contact  214   b  is provided in order to connect a second metal compound wiring layer  215   b  with the gate line  206 M 0  for the memory elements M 0  of the NAND strings NAND(0, 0) and NAND(0, 1). The contact  214   c  is provided in order to connect a 32nd metal compound wiring layer  215   c  with the gate line  206 M 30  for the memory elements M 30  of the NAND strings NAND(0, 0) and NAND(0, 1). The contact  214   d  is provided in order to connect a 33rd metal compound wiring layer  215   d  with the gate line  206 M 31  for the memory elements M 31  of the NAND strings NAND(0, 0) and NAND(0, 1). The contact  214   e  is provided in order to connect a 34th metal compound wiring layer  215   e  with the gate line  206 Mss for the source selection transistors STS of the NAND strings NAND(0, 0) and NAND(0, 1). The first metal compound wiring layer  215   a , the second metal compound wiring layer  215   b , the 32nd metal compound wiring layer  215   c , the 33rd metal compound wiring layer  215   d , and the 34th metal compound wiring layer  215   e  correspond to the first to fourth metal compound wiring layers  115   a ,  115   b ,  115   c , and  115   d  illustrated in the first to third embodiments. The drain selection transistor STD, the memory elements M 0  to M 31 , and the source selection transistor STS are vertically stacked in each of the NAND strings NAND(0, 0) and NAND(0, 1). 
         [0160]    Description will be given by referring to  FIG. 5A  and  FIG. 5B , which is a cross-sectional view taken along cut line A-A′ in  FIG. 5A . Planar silicon layers  202   nsd ,  202   n   0 , . . . ,  202   n   30 ,  202   n   31 , and  202   nss  are formed on an insulating film, such as a BOX layer  201 , formed on a substrate. The planar silicon layers  202   nsd ,  202   n   0 , . . . ,  202   n   30 ,  202   n   31 , and  202   nss  are respectively formed of n +  diffusion layers formed by impurity implantation or the like. Reference numeral  203  denotes a silicide layer formed on the surface of each of the planar silicon layers  202   nsd ,  202   n   0 , . . . ,  202   n   30 ,  202   n   31 , and  202   nss.    
         [0161]    Reference numerals  204   psd ,  204   p   0 , . . . ,  204   p   30 ,  204   p   31 , and  204   pss  each denote a p-type silicon pillar. Reference numeral  205  denotes a gate insulating film that surrounds the silicon pillars  204   psd ,  204   p   0 , . . . ,  204   p   30 ,  204   p   31 , and  204   pss . Reference numeral  206  denotes a gate electrode. Reference numeral  206   a  denotes a gate line. The gate insulating film  205  is also formed under the gate electrode  206  and the gate line  206   a.    
         [0162]    On the top portions of the silicon pillars  204   psd ,  204   p   0 , . . . ,  204   p   30 ,  204   p   31 , and  204   pss , n +  diffusion layers  207   nsd ,  207   n   0 , . . . ,  207   n   30 ,  207   n   31 , and  207   nss  are formed by impurity implantation or the like. Reference numeral  208  denotes a silicon-nitride film for protecting the gate insulating film  205 . Reference numerals  209   nsd ,  209   n   0 , . . . ,  209   n   30 ,  209   n   31 , and  209   nss  denote silicide layers connected to the n +  diffusion layers  207   nsd ,  207   n   0 , . . . ,  207   n   30 ,  207   n   31 , and  207   nss , respectively. 
         [0163]    Reference numerals  210   nsd ,  210   n   0 , . . . ,  210   n   30 ,  210   n   31 , and  210   nss  denote contacts. The contact  210   nsd  connects the silicide layer  209   nsd  with a line  213   a  of the first metal wiring layer. The contact  210   n   0  connects the silicide layer  209   n   0  with a line  213   c  of the first metal wiring layer. The contact  210   n   30  connects the silicide layer  210   n   30  with a line  213   e  of the first metal wiring layer. The contact  210   n   31  connects the silicide layer  210   n   31  with a line  213   g  of the first metal wiring layer. The contact  210   nss  connects the silicide layer  209   nss  with a line  213   i  of the first metal wiring layer. Reference numerals  214   nsd ,  214   n   0 , . . . ,  214   n   30 ,  214   n   31 , and  214   nss  denote contacts. The contact  214   nsd  connects the line  213   a  of the first metal wiring layer with a line  215   a  of the first metal compound wiring layer. The contact  214   n   0  connects the line  213   c  of the first metal wiring layer with a line  215   b  of the second metal compound wiring layer. The contact  214   n   30  connects the line  213   e  of the first metal wiring layer with a line  215   c  of the 32nd metal compound wiring layer. The contact  214   n   31  connects the line  213   g  of the first metal wiring layer with a line  215   d  of the 33rd metal compound wiring layer. The contact  214   nss  connects the line  213   i  of the first metal wiring layer with a line  215   e  of the 34th metal compound wiring layer. The lines  215   a ,  215   b ,  215   c ,  215   d , and  215   e  are respectively connected to the gate lines  206 Msd,  206 M 0 , . . . ,  206 M 30 ,  206 M 31 , and  206 Mss for the vertically-stacked transistors of the NAND strings. 
         [0164]    Reference numeral  212   a  denotes a contact that connects a line  213   b  of the first metal wiring layer with the lower diffusion layer  202   nsd  via the silicide layer  203 . Reference numeral  212   b  denotes a contact that connects a line  213   d  of the first metal wiring layer with the lower diffusion layer  202   n   0  via the silicide layer  203 . Reference numeral  212   c  denotes a contact that connects a line  213   f  of the first metal wiring layer with the lower diffusion layer  202   n   30  via the silicide layer  203 . Reference numeral  212   d  denotes a contact that connects a line  213   h  of the first metal wiring layer with the lower diffusion layer  202   n   31  via the silicide layer  203 . Reference numeral  212   e  denotes a contact that connects a line  213   j  of the first metal wiring layer with the lower diffusion layer  202   nss  via the silicide layer  203 . 
         [0165]    The silicon pillar  204   psd , the lower diffusion layer  202   nsd , the upper diffusion layer  207   nsd , the gate insulating film  205 , and the gate electrode  206  constitute the NMOS transistor Tnsd. The silicon pillar  204   p   0 , the lower diffusion layer  202   n   0 , the upper diffusion layer  207   n   0 , the gate insulating film  205 , and the gate electrode  206  constitute the NMOS transistor Tn 0 . The silicon pillar  204   p   30 , the lower diffusion layer  202   n   30 , the upper diffusion layer  207   n   30 , the gate insulating film  205 , and the gate electrode  206  constitute the NMOS transistor Tn 30 . The silicon pillar  204   p   31 , the lower diffusion layer  202   n   31 , the upper diffusion layer  207   n   31 , the gate insulating film  205 , and the gate electrode  206  constitute the NMOS transistor Tn 31 . The silicon pillar  204   pss , the lower diffusion layer  202   nss , the upper diffusion layer  207   nss , the gate insulating film  205 , and the gate electrode  206  constitute the NMOS transistor Tnss. 
         [0166]    To the gate electrodes  206  of the NMOS transistors Tnsd, Tn 0 , . . . , Tn 30 , Tn 31 , and Tnss, the gate line  206   a  is connected. 
         [0167]    The lower diffusion layer  202   nsd  serves as a common drain of the NMOS transistors Tnsd (four transistors are disposed in the longitudinal direction in  FIG. 5A ) via the silicide layer  203 . The lower diffusion layer  202   nsd  is connected to the line  213   b  of the first metal wiring layer via the contacts  212   a  (four contacts are disposed in the longitudinal direction in  FIG. 5A ), and the selection signal φsd is fed to the line  213   b.    
         [0168]    The lower diffusion layer  202   n   0  serves as a common drain of the NMOS transistors Tn 0  (four transistors are disposed in the longitudinal direction in  FIG. 5A ) via the silicide layer  203 . The lower diffusion layer  202   n   0  is connected to the line  213   d  of the first metal wiring layer via the contacts  212   b  (four contacts are disposed in the longitudinal direction in  FIG. 5A ), and the selection signal φ 0  is fed to the line  213   d.    
         [0169]    The lower diffusion layer  202   n   30  serves as a common drain of the NMOS transistors Tn 30  (four transistors are disposed in the longitudinal direction in  FIG. 5A ) via the silicide layer  203 . The lower diffusion layer  202   n   30  is connected to the line  213   f  of the first metal wiring layer via the contacts  212   c  (four contacts are disposed in the longitudinal direction in  FIG. 5A ), and the selection signal φ 30  is fed to the line  213   f.    
         [0170]    The lower diffusion layer  202   n   31  serves as a common drain of the NMOS transistors Tn 31  (four transistors are disposed in the longitudinal direction in  FIG. 5A ) via the silicide layer  203 . The lower diffusion layer  202   n   31  is connected to the line  213   h  of the first metal wiring layer via the contacts  212   d  (four contacts are disposed in the longitudinal direction in  FIG. 5A ), and the selection signal φ 31  is fed to the line  213   h.    
         [0171]    The lower diffusion layer  202   nss  serves as a common drain of the NMOS transistors Tnss (four transistors are disposed in the longitudinal direction in  FIG. 5A ) via the silicide layer  203 . The lower diffusion layer  202   nss  is connected to the line  213   j  of the first metal wiring layer via the contacts  212   e  (four contacts are disposed in the longitudinal direction in  FIG. 5A ), and the selection signal φss is fed to the line  213   j.    
         [0172]    The upper diffusion layer  207   nsd  that serves as the source of the NMOS transistor Tnsd is connected to the gate line  206 Msd that is a common gate line for the drain selection transistors STD of the NAND strings NAND(0, 0) and NAND(0, 1) via the contact  210   nsd , the line  213   a  of the first metal wiring layer, the contact  214   nsd , the line  215   a  of the first metal compound wiring layer, and the contact  214   a.    
         [0173]    The upper diffusion layer  207   n   0  that serves as the source of the NMOS transistor Tn 0  is connected to the gate line  206 M 0  that is a common gate line for the memory elements M 0  of the NAND strings NAND(0, 0) and NAND(0, 1) via the contact  210   n   0 , the line  213   c  of the first metal wiring layer, the contact  214   n   0 , the line  215   b  of the first metal compound wiring layer, and the contact  214   b.    
         [0174]    The upper diffusion layer  207   n   30  that serves as the source of the NMOS transistor Tn 30  is connected to the gate line  206 M 30  that is a common gate line for the memory elements M 30  of the NAND strings NAND(0, 0) and NAND(0, 1) via the contact  210   n   30 , the line  213   e  of the first metal wiring layer, the contact  214   n   30 , the line  215   c  of the 32nd metal compound wiring layer, and the contact  214   c.    
         [0175]    The upper diffusion layer  207   n   31  that serves as the source of the NMOS transistor Tn 31  is connected to the gate line  206 M 31  that is a common gate line for the memory elements M 31  of the NAND strings NAND(0, 0) and NAND(0, 1) via the contact  210   n   31 , the line  213   g  of the first metal wiring layer, the contact  214   n   31 , the line  215   d  of the 33rd metal compound wiring layer, and the contact  214   d.    
         [0176]    The upper diffusion layer  207   nss  that serves as the source of the NMOS transistor Tnss is connected to the gate line  206 Mss that is a common gate line for the source selection transistors STS of the NAND strings NAND(0, 0) and NAND(0, 1) via the contact  210   nss , the line  213   i  of the first metal wiring layer, the contact  214   nss , the line  215   e  of the 34th metal compound wiring layer, and the contact  214   e.    
         [0177]    The gate line  206   a  is connected to a line  213   k  of the first metal wiring layer via a contact  211   a , and RD 0  output from the row selection decoders  200   j  and  300   j , which are not illustrated, is fed to the line  213   k.    
         [0178]    Although the same reference numerals are used, a similar configuration is employed for RD 1  to RD 3  output from the row selection decoders. 
         [0179]    According to this embodiment, by using SGTs, a decoder having a reduced area, which operates as follows, can be provided. That is, the selection signals φsd, φ 0 , . . . , φ 30 , φ 31 , and φss are fed to the lower diffusion layers  202   nsd ,  202   n   0 , . . . ,  202   n   30 ,  202   n   31 , and  202   nss  that extend in the longitudinal direction via the contacts  212   a ,  212   b ,  212   c ,  212   d , and  212   e  respectively from the lines  213   b ,  213   d ,  213   f ,  213   h , and  213   j  formed in the first metal wiring layer, which are also disposed so as to extend in the longitudinal direction. Selection from among the first metal compound wiring layer  215   a , the second metal compound wiring layer  215   b , the 32nd metal compound wiring layer  215   c , the 33rd metal compound wiring layer  215   d , and the 34th metal compound wiring layer  215   e  is made, which are respectively connected to the gate electrodes of the selection transistors STD, the memory elements M 0 , the memory elements M 30 , the memory elements M 31 , and the selection transistors STS of the NAND strings NAND(j, k) (j=0 to 3, k=0 and 1), in accordance with any one signal selected from among the selection signals RD 0  to RD 3  of the row decoder, which is not illustrated, via the selection transistors Tnsd, Tn 0 , Tn 30 , Tn 31 , and Tnss that are arranged in a matrix form. 
         [0180]    As described in the second embodiment, by using the lines of the first metal wiring layer as metal lines for the decoder in this embodiment, manufacturing relating to the peripheral element region on the left side of  FIG. 5B  can be performed in the same manufacturing process as other peripheral circuit devices, which are not illustrated. As a result, a complex manufacturing process is not necessary. 
         [0181]    That is, a process of manufacturing portions up to the first metal wiring layer  213  including the selection transistors Tnsd, Tn 0 , Tn 30 , Tn 31 , and Tnss can be performed simultaneously with a process of manufacturing a logic circuit or the like to be disposed in other regions, which is not illustrated, thereby reducing an extra manufacturing process. 
       Fifth Embodiment 
       [0182]    A fifth embodiment is illustrated in  FIGS. 6A and 6B .  FIG. 6A  is a plan view of a layout (arrangement) of a word line selection decoder according to this embodiment of the present invention.  FIG. 6B  is a cross-sectional view taken along cut line A-A′ in  FIG. 6A . An equivalent circuit in this embodiment is based on the NAND string selection decoder  100  in  FIG. 1 . In  FIGS. 6A and 6B , BL 110   c  illustrated in the third embodiment ( FIGS. 4A to 4F ) is employed as the memory element selection decoder  110 . 
         [0183]    Note that cross-sectional views taken along the longitudinal direction in  FIG. 6A  are the same as  FIGS. 4D ,  4 E, and  4 F, which are cross-sectional views taken along the longitudinal direction in  FIG. 4A , and therefore, the cross-sectional views taken along the longitudinal direction in  FIG. 6A  will be omitted here. 
         [0184]      FIGS. 6A and 6B  illustrate a configuration that includes SGT-NAND strings as illustrated in the NAND string selection decoder  100  in  FIG. 1 . That is, eight NAND strings NAND(j, k) (j=0 to 3, k=0 and 1) are arranged in a matrix form, and each NAND string NAND(j, k) includes the drain selection transistor STD, the memory elements M 0  to M 31 , and the source selection transistor STS, that is, 34 elements in total, which are vertically stacked and disposed in order in series. 
         [0185]    Note that the configuration of the NAND strings is the same as that illustrated in  FIGS. 5A and 5B , and therefore, detailed description will be omitted. 
         [0186]    In  FIGS. 6A and 6B , a portion having the same structure as the corresponding one in  FIGS. 4A ,  4 B,  4 C,  4 D,  4 E,  4 F,  5 A, and  5 B is denoted by a corresponding reference numeral in the two hundreds. 
         [0187]    A difference between  FIGS. 6A and 6B  and  FIGS. 5A and 5B  is similar to the difference between  FIGS. 3A to 3F  and  FIGS. 4A to 4F . That is, while the second selection signal lines φsd, φ 0 , φ 30 , φ 31 , and φss are formed in the first metal wiring layer and are disposed below the line  215   e  of the 34th metal compound wiring layer in  FIGS. 5A and 5B , the second selection signal lines φsd, φ 0 , φ 30 , φ 31 , and φss are formed in the second metal wiring layer and are disposed above the line  215   a  of the first metal compound wiring layer in  FIGS. 6A and 6B . The reason for such a configuration has been as described above. The second selection signal lines φsd, φ 0 , φ 30 , φ 31 , and φss are formed as lines of the second metal wiring layer, that is, lines in the same metal wiring layer in which bit lines  216 M 0  and  216 M 1  of the NAND strings are formed to thereby simplify the manufacturing process. 
         [0188]    However, the contact  211   a  that connects a line  216   f  of the second metal wiring layer to which an output row selection signal RDj of a row decoder is fed and the gate line  206   a  has the maximum height (depth). Therefore, it is necessary to pay attention in a case of creating this contact. 
         [0189]    According to this embodiment, by using SGTs, a decoder having a reduced area, which operates as follows, can be provided. That is, the selection signals φsd, φ 0 , . . . , φ 30  , φ 31 , and φss are fed to the lower diffusion layers  202   nsd ,  202   n   0 , . . . ,  202   n   30 ,  202   n   31 , and  202   nss  that extend in the longitudinal direction via the contacts  212   a ,  212   b ,  212   c ,  212   d , and  212   e  respectively from the lines  216   a ,  216   b ,  216   c ,  216   d , and  216   e  formed in the second metal wiring layer, which are also disposed so as to extend in the longitudinal direction. Selection from among the lines  215   a ,  215   b ,  215   c ,  215   d , and  215   e  is made, which are respectively connected to the gate electrodes of the selection transistors STD, the memory elements M 0 , the memory elements M 30 , the memory elements M 31 , and the selection transistors STS of the NAND strings NAND(j, k) (j=0 to 3, k=0 and 1), in accordance with any one signal selected from among the selection signals RD 0  to RD 3  of the row decoder, which is not illustrated, via the selection transistors Tnsd, Tn 0 , Tn 30 , Tn 31 , and Tnss that are arranged in a matrix form. 
         [0190]    Furthermore, according to this embodiment, lines of the same second metal wiring layer in which the bit lines of the NAND strings are formed are used as metal lines for the decoder to thereby simplify the manufacturing process. 
         [0191]    In the embodiments, description has been given while assuming that a metal compound is used as a material of the lines  115   a ,  115   b ,  115   c ,  115   d ,  215   a ,  215   b ,  215   c ,  215   d , and  215   e  that are connected to word lines in order to make the film thickness as thin as possible. However, general metal wiring layers may be used. 
         [0192]    In the embodiments, description has been given while assuming the BOX structure. However, the embodiments can be implemented using a usual CMOS structure, and therefore, the structure is not limited to the BOX structure. 
         [0193]    In the description of the embodiments, the NMOS silicon pillars are defined as p-type silicon layers, for convenience sake. However, the concentration control in a case of impurity implantation is difficult in a miniaturized process. Therefore, there may be a case where so-called neutral (intrinsic) semiconductors, in which no impurity implantation is involved, are used as silicon pillars for both PMOS transistors and NMOS transistors, and channels are controlled, that is, the thresholds for PMOS and NMOS are controlled by using a difference in the work function specific to the metal gate material. 
         [0194]    In the embodiments, the lower diffusion layer or the upper diffusion layer is covered by a silicide layer. Silicide is employed in order to lower the resistance. Other low-resistance materials may be used. As a generic term of a metal compound, silicide is defined to be the material. 
         [0195]    The present invention is characterized in that the sources or drains of selection transistors that form memory cells are connected with each other via the lower diffusion layer, and are used as a wiring region, which is a feature of an SGT, to thereby omit a dedicated wiring region and provide a column selection gate decoder having a reduced area. As long as the arrangement method of the present invention is employed, a wiring method and wiring positions relating to the gate lines, a wiring method and wiring positions relating to the metal lines, and the like other than those illustrated in the drawings of the embodiments fall within the technical scope of the present invention.

Technology Classification (CPC): 7