Patent Publication Number: US-11037950-B2

Title: Semiconductor memory device, semiconductor device, and method of manufacturing semiconductor device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2018-0082208, filed on Jul. 16, 2018, in the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference in its entirety. 
     BACKGROUND 
     The inventive concept relates to a semiconductor memory device, a semiconductor device structure, a semiconductor device, and a method of manufacturing a semiconductor device. For example, the disclosure is related to a semiconductor memory device, a semiconductor device structure, and a semiconductor device that may maintain a high operation speed with high reliability and may be manufactured at a low cost. 
     For highly integration of semiconductor devices, there have been suggested vertical semiconductor devices including a vertical and horizontal array of memory cells arranged in three dimensions. Various methods of increasing the operation speed of semiconductor devices have been suggested recently. However, such methods may reduce the reliability and/or durability of a semiconductor device, or may require costly processes. Therefore, there is a high demand for a method of manufacturing a semiconductor device that has a high operation speed and improved reliability at reduced cost. 
     SUMMARY 
     The disclosed embodiments provide a semiconductor memory device that may maintain a high operation speed, high reliability and may be manufactured at reduced cost. 
     The disclosed embodiments provide a semiconductor structure that may maintain a high operation speed, high reliability and may be manufactured at reduced cost. 
     According to an aspect of the inventive concept, there is provided a semiconductor memory device including: a substrate including a cell region on which memory cells are disposed and a connection region on which conductive patterns are disposed, the conductive patterns electrically connected to the memory cells; a first word line stack including a plurality of first word lines that are stacked on the substrate in the cell region and extend to the connection region; a second word line stack including a plurality of second word lines that are stacked on the substrate in the cell region and extend to the connection region, the second word line stack being adjacent to the first word line stack; vertical channels disposed on the cell region of the substrate, the vertical channels being connected to the substrate and respectively coupled with the plurality of first and second word lines; a bridge connecting one of the plurality of first word lines in the first word line stack to a corresponding word line of the second word line stack; and a first pattern formed between a first ground selection line (GSL) and a second GSL, wherein the first pattern and the bridge overlaps in a plan view, and wherein the first pattern includes a sub-pattern spaced apart from at least one of the two GSLs in a horizontal direction. 
     According to another aspect of the inventive concept, there is provided a semiconductor device including: a first and a second conductive patterns extending parallel to a first direction on a semiconductor substrate, the first conductive pattern having a first width and the second conductive pattern having a second width; a first pattern formed between the first and second conductive patterns in a plan view; a first insulating layer formed on the first and second conductive patterns; and a second insulating layer formed on the first insulating layer, wherein the first pattern includes: a sub-pattern having a conductive material different from a material of the first and second conductive patterns; and a first insulator contacting side surfaces of the sub-pattern, wherein the sub-pattern has a narrower width than the first and second widths of the respective first and second conductive patterns. 
     According to another aspect of the inventive concept, there is provided a semiconductor device including: a first horizontal electrode extending in a first direction on a semiconductor substrate; a second horizontal electrode extending in the first direction and spaced apart from the first horizontal electrode at the same vertical height above the semiconductor substrate as the first horizontal electrode; a first pattern arranged between the first horizontal electrode and the second horizontal electrode to electrically insulate the first horizontal electrode from the second horizontal electrode; and a conductor and an insulator stacked on the first horizontal electrode, the second horizontal electrode, and the first pattern, wherein the first pattern includes a plurality of sub-patterns spaced apart from each other, wherein the sub-patterns are spaced apart from the first and second horizontal electrodes, and wherein the spaced apart distances between adjacent sub-patterns of the plurality of sub-patterns and the respective spaced apart distances between the sub-patterns and the horizontal electrodes are about 3 nm to about 100 nm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the inventive concept will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a block diagram of a 3-dimensional (3D) semiconductor memory device according to an embodiment; 
         FIG. 2  is a circuit diagram of a cell array of a 3D semiconductor memory device according to an embodiment; 
         FIG. 3  is a perspective view of a cell array of a 3D semiconductor memory device according to an embodiment; 
         FIG. 4A  is a partial perspective view of an end portion of a vertical semiconductor memory device according to an embodiment; 
         FIG. 4B  is a side view of the vertical semiconductor memory device of  FIG. 4A  taken from a second direction D 2 ; 
         FIG. 5  is a plan view of an end portion of the vertical semiconductor memory device of  FIG. 4A ; 
         FIG. 6  is a plan view separately showing a ground selection line of a first word line stack and a ground selection line of a second word line stack; 
         FIG. 7A  is a plan view of a cut pattern according to an embodiment;  FIG. 7B  is a cross-sectional view taken along a line B-B′ of  FIG. 7A ; 
         FIGS. 8 to 14  are plan views of cut patterns according to certain embodiments; 
         FIGS. 15A to 15J  are cross-sectional views for describing a method of manufacturing a semiconductor memory device in order, according to an embodiment; 
         FIG. 16  is a cross-sectional view of a bridge when ground selection lines and word lines are arranged without using a cut pattern; 
         FIG. 17A  is an enlarged view showing a region C of  FIG. 15E  in detail; 
         FIG. 17B  is an enlarged view showing a region C of  FIG. 15F  in detail; 
         FIG. 17C  is an enlarged view showing a region C of  FIG. 15I  in detail; 
         FIG. 18  is a cross-sectional view illustrating a cell column of a semiconductor memory device according to an embodiment; and 
         FIGS. 19A and 19B  are perspective views for describing a method of forming an upper layer having a flat upper surface on an upper portion of a lower layer having a relatively large/deep recess pattern. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of a 3-dimensional (3D) semiconductor memory device according to an embodiment. 
     Referring to  FIG. 1 , a 3D semiconductor memory device according to an exemplary embodiment may include a cell array region A, a connection region B, and a peripheral circuit region C. 
     In the cell array region A, memory cells arranged in three dimensions, and bit lines and word lines, which may be electrically connected with the memory cells, may be formed. In the connection region B, which may be disposed between the cell array region A and the peripheral circuit region C, contact plugs and other wiring that may connect the memory cells to peripheral circuits may be formed. In the peripheral circuit region C, peripheral circuits for driving the memory cells and reading data stored in the memory cells may be formed. For example, in the peripheral circuit region C, a word line (WL) driver, a sense amplifier, a row decoder, a column decoder, and control circuits may be formed. 
       FIG. 2  is a circuit diagram of a cell array of a 3D semiconductor memory device according to an embodiment.  FIG. 3  is a perspective view of a cell array of the 3D semiconductor memory device according to an embodiment. 
     Referring to  FIG. 2 , a cell array of a 3D semiconductor memory device according to an embodiment may include a plurality of common source lines CSL, a plurality of bit lines BL, and a plurality of cell strings CSTR disposed between the common source lines CSL and the plurality of bit lines BL. 
     The plurality of bit lines BL may be arranged in two dimensions and may be connected in parallel to the plurality of cell strings CSTR. For example, plural bit lines BL may arranged in a first direction, each of which may extend in a second direction perpendicular to the first direction. 
     The plurality of cell strings CSTR may be connected in common to a corresponding common source line CSL. For example, the plurality of cell strings CSTR may be disposed between the plurality of bit lines BL and one common source line CSL. The plurality of common source lines CSL may be arranged in two dimensions. For example, plural common source lines may extend in a first direction and be arranged in a second direction. The same voltage may be electrically applied to the plurality of common source lines CSL. In some embodiments, the plurality of common source lines CSL may be each independently electrically controlled. 
     Each of the plurality of cell strings CSTR may include a ground selection transistor GST connected to a common source line CSL, a string selection transistor SST connected to a bit line BL, and a plurality of memory cell transistors MCT disposed between the ground selection transistor GST and the string selection transistor SST. The ground selection transistor GST, the string selection transistor SST, and the memory cell transistors MCT may be connected in series to one another. 
     The common source line CSL may be connected in common to sources of the ground selection transistors GST. Ground selection lines GSL, a plurality of word lines WL 0  to WL 3 , and a plurality of string selection lines SSL, which are disposed between the common source lines CSL and the bit lines BL, may be used as gate electrodes of the ground selection transistors GST, the memory cell transistors MCT, and the string selection transistors SST, respectively. The memory cell transistors MCT may each include a data storage element. 
     Referring to  FIG. 3 , a substrate  110  may be provided. The substrate  110  may be a first conductive type, for example, a P type. A buffer dielectric film  122  may be provided on the substrate  110 . The buffer dielectric film  122  may include a silicon oxide film such as a middle temperature oxide (MTO) film. Insulating patterns  125  and horizontal electrodes isolated from each other by the insulating patterns  125  may be provided on the buffer dielectric film  122 . 
     The horizontal electrodes may include a ground selection line GSL, first to fourth word lines WL 0  to WL 3 , and string selection lines SSL. The insulating patterns  125  may include silicon oxide films. The thickness of the buffer dielectric film  122  may be less than the thickness of each insulating pattern  125 . The horizontal electrodes may include doped silicon, metal (for example, tungsten), metal nitride (for example, titanium nitride), metal silicide, or a combination thereof. For example, each of the horizontal electrodes may include a barrier layer and a metal layer on the barrier layer. The barrier layer may include metal nitride, for example, titanium nitride. The metal layer may include, for example, tungsten. 
     The insulating patterns  125  and the horizontal electrodes may constitute a gate structure G. The gate structure G may horizontally extend in a first direction D 1 . A plurality of gate structures G may be provided on the substrate  110 . The gate structures G may face one another in a second direction D 2  that intersects the first direction D 1 . The string selection lines SSL may be separated from one another in the second direction D 2  and may extend in the first direction D 1 . Although a gate structure G in  FIG. 3  is illustrated as including a plurality of string selection lines SSL 1  and SSL 2  and one ground selection line GSL, the invention are not limited thereto. 
     An isolation region  121  that extends in the first direction D 1  may be provided between two adjacent gate structures G. Common source lines CSL may be provided in the isolation regions  121  in the substrate  110 . The common source lines CSL may be separated from one another and may extend in the substrate  110  in the first direction D 1 . The common source lines CSL may be a second conductive type, for example, an N type, that is different from the first conductive type. Unlike  FIG. 3 , the common source lines CSL may be provided between two adjacent ground selection lines GSL on the substrate  110 , and may be a line pattern extending in the first direction D 1 . For example, the ground selection lines GSL may be formed on the substrate  110  with a conductor pattern in certain embodiments. 
     A plurality of cell columns PL may be connected to the substrate  110  through the horizontal electrodes such as ground selection lines GSL, the first to fourth word lines WL 0  to WL 3 , and the string selection lines SSL. The cell columns PL may have a major axis that may vertically extend upwards from the substrate  110  (i.e., in a third direction D 3 ). An end of each of the cell columns PL may be connected to the substrate  110 , and the opposite end thereof may be connected to wirings that extend in the second direction D 2 . The wirings may include a first wiring BL 1  and a second wiring BL 2 , which may be adjacent to each other and extend in the second direction D 2 . 
     A plurality of cell columns PL connected to one string selection line SSL may be in a zig-zag or staggered fashion. The plurality of cell columns PL may include first cell columns PL 1  and second cell columns PL 2  that may be connected to one string selection line SSL. The first cell columns PL 1  may be adjacent to the isolation region  121 , whereas the second cell columns PL 2  may be relatively away from the isolation region  121 . For example, the first cell columns PL 1  may be closer to the corresponding isolation region  121  than the second cell columns PL 2 . The second cell columns PL 2  may be shifted from the first cell columns PL 1  in the first direction D 1  and the second direction D 2 . The first cell columns PL 1  and the second cell columns PL 2  may be connected to a first upper wiring BL 1  and a second upper wiring BL 2 , respectively, via conductive patterns  136  and contacts  138 . 
     A plurality of cell strings CSTR may be provided between the first and second upper wirings BL 1  and BL 2  and the common source lines CSL. The first and second upper wirings BL 1  and BL 2  may include bit lines of a flash memory device. Each cell string CSTR may include a string selection transistor SST connected to the first and second upper wirings BL 1  and BL 2 , a ground selection transistor GST connected to the common source lines CSL, and a plurality of vertical string memory cells between the string selection transistor and the ground selection transistor. The ground selection line GSL may correspond to a ground selection gate of the ground selection transistor, the first to fourth word lines WL 0  to WL 3  may correspond to cell gates of the plurality of vertical string memory cells, and the string selection line SSL may correspond to a string selection gate of the string selection transistor. Each cell column PL may include a plurality of memory cells MC. The ground selection gate may be a ground selection gate of a flash memory device. The string selection gate may be a string selection gate of a flash memory device. 
     A data storage element  130  may be provided between the first to fourth word lines WL 0  to WL 3  and the cell columns PL. The data storage element  130  may include a charge storage layer. For example, the data storage element  130  may include one of a trap insulating layer, a floating gate electrode, and an insulating layer including conductive nanodots. As illustrated in  FIG. 3 , the data storage element  130  may extend between the insulating patterns  125  and the first to fourth word lines WL 0  to WL 3 . In some other embodiments, at least a part of the data storage element  130  may extend between the insulating patterns  125  and the cell columns PL. A gate insulating layer, instead of the data storage element  130 , may be provided between the string selection lines SSL and the cell columns PL, and between ground selection lines GSL and the cell columns PL. For example, data storage elements  130  may not be formed between the string selection lines SSL and the cell columns PL, and between the ground selection lines GSL and the cell columns PL. 
     A dielectric layer used as a gate insulating layer of a transistor may be disposed between the ground selection lines GSL and the cell columns PL, or between the string selection lines SSL 1  and SSL 2  and the cell columns PL. The dielectric layer may be formed of the same material as the data storage element  130 . The dielectric layer may include a conventional gate insulating layer for a metal oxide semiconductor field-effect transistor (MOSFET), for example, may include a silicon oxide layer. 
     In this structure, the cell columns PL may constitute a MOSFET together with the ground selection lines GSL, the first to fourth word lines WL 0  to WL 3 , and the string selection lines SSL 1  and SSL 2 , wherein the cell columns PL may serve as channel regions of the MOSFET. In some other embodiments, the cell columns PL may constitute a metal oxide silicon (MOS) capacitor together with the ground selection lines GSL, the word lines WL 0  to WL 3 , and the string selection lines SSL 1  and SSL 2 . 
     The ground selection lines GSL and the string selection lines SSL 1  and SSL 2  may be used as gate electrodes of selection transistors, and the first to fourth word lines WL 0  to WL 3  may be used as gate electrodes of cell transistors. A fringe field generated by a voltage applied to the ground selection lines GSL, the word lines WL 0  to WL 3 , and the string selection lines SSL 1  and SSL 2  may form inversion regions in the cell columns PL. A maximum length (or width) of the inversion regions may be greater than a thickness of the first to fourth word lines WL 0  to WL 3  or the string and the ground selection lines SSL, SSL 2 , and GSL that form the inversion regions. Accordingly, the inversion regions formed in the cell columns PL may vertically overlap with one another to form a current path through which a selected bit line is electrically connected with the common source line CSL. The cell strings CSTR may have a structure in which the ground selection transistors and the string selection transistors respectively connected to the ground selection lines GSL and the string selection lines SSL 1  are connected in series with the memory cell transistors (MCT, see  FIG. 2 ) connected to the word lines WL 0  to WL 3 . 
     In some embodiments, dummy word lines DM 1  and DM 2  may be disposed between the string selection lines SSL 1  and SSL 2  and the first to fourth word lines WL 0  to WL 3 . The dummy word lines DM 1  and DM 2  may maintain distribution of threshold voltages in the string selection lines SSL 1  and SSL 2  uniform to prevent reduction in cell current. The dummy word lines described herein may receive certain voltages, but in one embodiment are not written to or read from by a controller. 
       FIG. 4A  is a perspective view of an end portion of a vertical semiconductor memory device according to an embodiment.  FIG. 4B  is a side view of the vertical semiconductor memory device of  FIG. 4A  taken from the second direction D 2 .  FIG. 5  is a plan view of an end portion of the vertical semiconductor memory device. 
     Referring to  FIGS. 4A, 4B, and 5 , a cell array region A and a connection region B may be adjacent to each other. The arrangement of the connection region B, including contact plugs and wirings that may connect memory cells and peripheral circuits, are arranged adjacent to the cell array region A. 
     In the connection region B, gate structures G may have a stepwise structure for electrical connection with a peripheral circuit region C (see  FIG. 1 ). In the stepwise structure, the gate structures G may extend in a first direction D 1  in a stepwise fashion where the string selection lines SSL 2  and SSL 1 , the dummy word lines DM 2  and DM 1 , the word lines WL 3  to WL 0 , and the ground selection line GSL may extend gradually longer in the stated order and laterally protrude from corresponding upper horizontal electrodes. 
     The semiconductor memory device may include at least a first word line stack and a second word line stack. The first word line stack may include first word lines WLA stacked on one another in the cell array region A. The second word line stack may include second word lines WLB stacked on one another in the cell array region A. As described above, the first word lines WLA and the second word lines WLB may extend to the connection region B, and end portions thereof may have a stepwise structure. In some embodiments, the end portions of the first word lines WLA and the second word lines WLB in the connection region B may be bent and extend in a third direction D 3  that is a vertical direction. 
     The semiconductor memory device may further include a third word line stack and a fourth word line stack, adjacent to the first word line stack and the second word line stack. Structures of the third word line stack and the fourth word line stack may be substantially the same as the structures of the first word line stack and the second word line stack, and thus a description thereof will not be provided here. For example, each word line stack may include a ground selection line, a plurality of word lines, and a string selection line. In certain embodiments, each word line stack may include a dummy word line. 
     The first to fourth word line stacks may constitute one memory block. In some embodiments, the first word line stack and the second word line stack may constitute one memory block. 
     A string selection line SSL of the first word line stack and a string selection line SSL of the second word line stack may be physically and electrically separated from each other. 
     In the cell array region A, the first word line stack to the fourth word line stack may be separated from one another by the isolation region  121 . For example, an isolation pattern may be formed in the isolation region  121 . In some embodiments, the first word line stack and the second word line stack may be partially connected to one another in the connection region B. For example, the first to fourth word lines WL 0  to WL 3  and the dummy word lines DM of the first word line stack may be connected with the word lines WL 0  to WL 3  and the dummy word lines DM of the second word line stack. 
     In some embodiments, the first word line stack to the fourth word line stack may be at least partially connected to one another in the connection region B. For example, the first to fourth word lines WL 0  to WL 3  and the dummy word lines DM of the first word line stack to the fourth word line stack may be connected to each other. 
     The first word line stack to the fourth word line stack may be connected to one another by bridges BG. For example, the first to fourth word lines WL 0  to WL 3  of the first word line stack may be connected to the corresponding first to fourth word lines WL 0  to WL 3  of the second to fourth word line stacks by bridges BG. For example, word lines disposed in different word line stacks may be electrically connected to each other by the bridges BG so that the electrically connected word lines may be applied with the same electric signal while the semiconductor memory device operates. The dummy word lines DM of the first word line stack may be connected to the corresponding dummy word lines DM of the second to fourth word line stacks by bridges BG. For example, dummy word lines DM disposed in different word line stacks may be electrically connected to each other by the bridges BG so that the electrically connected dummy word lines may be applied with the same electric signal while the semiconductor memory device operates. In  FIGS. 4A, 4B, and 5 , the width of the dummy word line DM 2  in the first direction D 1  is slightly exaggerated for a clear illustration of the bridges BD. The individual horizontal electrodes may protrude with substantially the same width in the first direction D 1 . For example, exposed portions of the electrodes by corresponding upper electrodes in the connection region B may have the same width in the first direction D 1 . 
     The ground selection line GSL of the first word line stack and the ground selection line GSL of the second word line stack may be physically separated from one another. The ground selection line GSL of the first word line stack may be physically connected to or may be integrated with the ground selection line GSL of the second word line stack. However, when the ground selection line GSL of the first word line stack is physically separated from the ground selection line GSL of the second word line stack, improved electrical characteristics such as high operation speed may be attained. 
     As described above, the first to fourth word lines WL 0 -WL 3  of the first to fourth word line stacks may be connected to the other word lines WL 0  to WL 3  of the first to fourth word line stacks by bridges BG. The dummy word lines DM of the first to fourth word line stacks may be connected to the other dummy word lines DM of the first to fourth word line stacks by the bridges BG. 
     Thus, any one of the first to fourth word lines WL 0  to WL 3  and the dummy word lines DM of the first to fourth word line stacks may be connected to the peripheral circuit region by only one upper wiring. For example, the word lines WL 3  of the first to fourth word line stacks may be connected to the peripheral circuit region only by an upper wiring UL 3 . Each word line stack does not need an upper wiring for connecting the corresponding layers on the same level to the peripheral circuit region. This is because the word lines of the different word line stacks on the corresponding layer at the same level are connected to one another by a bridge BG. 
     Such bridges may be formed at the same time as when the isolation regions  121  for isolating the first to fourth word line stacks are formed. However, this may cause the ground selection lines GSL at the lowermost level to be connected by the bridges BG. To prevent this, portions of the ground selection lines GSL that correspond to the bridges BG may be previously removed. While  FIG. 4A  illustrates that only the ground selection line GSL in the third word stack is connected to the peripheral circuit region by an upper wiring UL 7 , every ground selection line GSL may be connected to the peripheral circuit with a corresponding upper wiring in some embodiments in that ground selection lines are controlled independently from each other. 
       FIG. 6  is a plan view separately showing the first ground selection line GSL 1  of the first word line stack and the second ground selection line GSL 2  of the second word line stack, according to an example embodiment. 
     Referring to  FIG. 6 , the first ground selection line GSL 1  and the second ground selection line GSL 2  may be conductive layers that are electrically insulated from each other by a cut pattern CP. In some embodiments, the cut pattern CP may be arranged at a location of the bridge BG (see  FIG. 5 ). For example, the cut pattern CP may be formed below the bridges BG electrically connecting respective word lines WL 0 -WL 3  and/or respective dummy word lines DM 1  and DM 2  formed in adjacent word line stacks. For example, while the first ground selection line GSL 1  and the second ground selection line GSL 2  are electrically insulated from each other by the isolation region  121  in which an isolation insulating layer  120  will be formed in a later step as shown in  FIG. 18 , the cut pattern CP also electrically insulating the first and second ground selection lines GSL 1  and GSL 2  from each other may be formed between the first and second ground selection lines GSL 1  and GSL 2 . 
     The cut pattern CP may electrically insulate the first ground selection line GSL 1  and the second ground selection line GSL 2  from each other. As shown in  FIG. 6 , an additional ground selection line may be further provided at a right side of the second ground selection line GSL 2 , and the second ground selection line GSL 2  may be electrically insulated from the additional ground selection line at the right side thereof by the cut pattern CP. For example, the cut pattern CP may be a pattern formed between the first and second ground selection lines GSL 1  and GSL 2  adjacent to each other in a plan view, the first and second ground selection lines GSL 1  and GSL 2  and the cut pattern CP may be formed on the substrate  110 , and the substrate  110  may form step structures with each of the first and second ground selection lines GSL 1  and GSL 2 . For example, the top surface of the substrate  110  and the top surfaces of the first and second ground selection lines GSL 1  and GSL 2  may have respective step structures. The cut pattern CP may reduce the step structures formed between the substrate  110  and the ground selection lines GSL 1  and GSL 2 . For example, the height between a top surface of the substrate  110  and a top surface of the ground selection lines may be greater than the height between a top surface of the cut pattern CP and a top surface of the ground selection lines GSL 1  and GSL 2 . In certain embodiments, the level of the top surface of the cut pattern CP and the levels of the top surfaces of the ground selection lines GSL 1  and GSL 2  may be the same or substantially the same. 
     As shown in  FIG. 6 , the first ground selection line GSL 1  may include a first recess portion R 1  contacting at least three side surfaces of the cut pattern CP. The second ground selection line GSL 2  may include a second recess portion R 2  contacting at least three side surfaces of the cut pattern CP. 
     The side surfaces of the cut pattern CP and the side surfaces of the bridge BG may be self-aligned because they are obtained by simultaneously etching the same etching mask, as described in detail later. 
     In  FIG. 6 , the cut pattern CP has an H-shaped plane (e.g., H-shaped plan view) as an example, but the cut pattern CP may have various planar shapes (e.g., plan views) varying depending on relative sizes between the bridge BG and the cut pattern CP, and the width and length of the isolation region  121 . This may be appreciated through a manufacturing method that will be described later. 
       FIGS. 7A and 8 to 14  are plan views of cut patterns CP according to some embodiments. 
       FIG. 7A  is a plan view of a cut pattern CP 1  according to an embodiment, and  FIG. 7B  is a cross-sectional view taken along a line B-B′ of  FIG. 7A . 
     Referring to  FIGS. 7A and 7B , the cut pattern CP 1  may include a narrow pattern P 1 . The narrow pattern P 1  may have a width W 1 . The narrow pattern P 1  may be electrically insulated from the first ground selection line GSL 1  and the second ground selection line GSL 2  by a cut pattern insulator P 2 . The cut pattern insulator P 2  may have a width W 2 . For example, the narrow pattern P 1  may be a sub-pattern included in the cut pattern CP 1 . For example, the cut pattern CP 1  may include a plurality of sub-patterns, e.g., a plurality of narrow patterns P 1 . 
     In some embodiments, the narrow pattern P 1  may include a different material from those of the first ground selection line GSL 1  and/or the second ground selection line GSL 2 . In some embodiments, the narrow pattern P 1  may be located at the same level as the first ground selection line GSL 1  and/or the second ground selection line GSL 2 . For example, the cut pattern CP 1  may include a plurality of narrow patterns P 1  in a plan view and/or in a cross-sectional view. 
     Here, the ‘narrow pattern’ may be an arbitrary pattern having a narrower width than those of the first ground selection line GSL 1  and/or the second ground selection line GSL 2  in the cut pattern CP 1 . The narrow pattern P 1  may be electrically connected to the first ground selection line GSL 1  or the second ground selection line GSL 2 , but is not electrically connected to both the first ground selection line GSL 1  and the second ground selection line GSL 2 . This is because the first ground selection line GSL 1  and the second ground selection line GSL 2  have to be electrically insulated from each other by the cut pattern CP 1 . For example, the narrow pattern P 1  may be made of a conductive material. 
     As shown in  FIG. 7B , the cut pattern insulator P 2  may be embedded in a space in the narrow pattern P 1 . In some embodiments, the cut pattern insulator P 2  may be embedded in a space between the narrow pattern P 1  and the first ground selection line GSL 1 . In some embodiments, the cut pattern insulator P 2  may be embedded in a space between the narrow pattern P 1  and the second ground selection line GSL 2 . 
     In some embodiments, a first insulating layer  124   a  may be provided on the cut pattern CP 1 . The first insulating layer  124   a  may include the same material as that of the cut pattern insulator P 2 . In some embodiments, the first insulating layer  124   a  may be integrally formed with the cut pattern insulator P 2 . For example, the first insulating layer  124   a  and the cut pattern insulator P 2  may form a continuous pattern and there may be no discontinuity (e.g., discontinuity surface) between the first insulating layer  124   a  and the cut pattern insulator P 2 . 
     The first insulating layer  124   a  may cover upper surfaces of the first ground selection line GSL 1  and the second ground selection line GSL 2 . As will be described in more detail later, the first insulating layer  124   a  and the cut pattern insulator P 2  may be formed simultaneously by an atomic layer deposition (ALD) process. However, the invention is not limited thereto. 
     Since the first insulating layer  124   a  and the cut pattern insulator P 2  are conformally embedded upward from the space between narrow patterns P 1  by the ALD process, a dense material layer without a void therein may be obtained. Also, since the first insulating layer  124   a  is formed by the ALD process, a substantially flat upper surface may be obtained. Terms s “same”, “equal,” “flat,” “planar,” or “coplanar,” as used in this disclosure when referring to orientation, layout, location, shapes, sizes, amounts, or other measures do not necessarily mean an exactly identical orientation, layout, location, shape, size, amount, or other measure, but are intended to encompass nearly identical orientation, layout, location, shapes, sizes, amounts, or other measures within acceptable variations that may occur, for example, due to manufacturing processes. The term “substantially” be used herein to emphasize this meaning, unless the context or other statements indicate otherwise. For example, items described as “substantially the same,” “substantially equal,” “substantially flat,” “substantially identical,” or “substantially planar,” may be exactly the same, equal, flat, identical, or planar, or may be the same, equal, flat, identical, or planar within acceptable variations that may occur, for example, due to manufacturing processes. 
     A distance between the narrow patterns P 1 , that is, the width W 2  of the cut pattern insulator P 2 , may have a dimension to be filled with the insulator with a sufficient speed by the ALD process. For example, the distance between the narrow patterns P 1  may be about 3 nm to about 100 nm. For the same reason as above, a distance between the narrow pattern P 1  and the first ground selection line GSL 1  and a distance between the narrow pattern P 1  and the second ground selection line GSL 2  may be about 3 nm to about 100 nm. 
     The space between the narrow patterns P 1  may have a dimension of about 3 nm to about 100 nm in at least one horizontal direction, e.g., in the first direction D 1  or in the second direction D 2 . When the space between the narrow patterns P 1  has a sufficiently narrow dimension in the at least one horizontal direction, the insulator may be embedded with a sufficient speed by the ALD process. 
     When the space between the narrow patterns P 1  is too narrow, an insulating effect by using the cut pattern insulator P 2  may be insufficient, and the cut pattern insulator P 2  may not be embedded dense. When the space between the narrow patterns P 1  is too wide, it takes an excessively long time period to form the cut pattern insulator P 2  and it may not be economically efficient. 
     In  FIG. 7A , the narrow pattern P 1  is shown to have rectangular patterns as an example, but the invention is not limited thereto. 
     Also, in  FIGS. 7A and 7B , a width WT of the cut pattern CP 1  is greater than a width WI of the isolation region  121 , but the invention is not limited thereto. In some embodiments, the width WI of the isolation region  121  may be greater than the width WT of the cut pattern CP 1 . This will be also applied to embodiments that will be described below. 
       FIG. 8  is a plan view of a cut pattern CP 2  according to an embodiment. 
     Referring to  FIG. 8 , the narrow pattern P 1  may include a plurality of line patterns extending in one direction (here, a direction in parallel with the direction D 1 ). The cut pattern insulator P 2  may include a surrounding portion P 21  extending along a perimeter of the cut pattern CP 2 . For example, the surrounding portion P 21  may form an outermost portion of the cut pattern CP 2 , and may surround the narrow patterns P 1 . The cut pattern insulator P 2  may include an inside filler P 22  filled in between the narrow patterns P 1 . 
       FIG. 9  is a plan view of a cut pattern CP 3  according to an embodiment. 
     Referring to  FIG. 9 , the narrow pattern P 1  may include a plurality of line patterns extending in one direction (here, a direction in parallel with the direction D 2 ). The embodiment illustrated in  FIG. 9  is substantially identical with the embodiment illustrated with reference to  FIG. 8  except for the direction in which the narrow pattern P 1  extends and the number of the line patterns, and thus, additional descriptions thereof are omitted here. 
       FIG. 10  is a plan view of a cut pattern CP 4  according to an embodiment. 
     Referring to  FIG. 10 , the narrow pattern P 1  may include a plurality of line patterns extending in one direction (here, a direction inclined with respect to directions D 1  and D 2 ). The embodiment illustrated in  FIG. 10  is substantially identical with the embodiment illustrated with reference to  FIG. 8  except for the direction in which the narrow pattern P 1  extends and the number and lengths of the line patterns, and thus, additional descriptions thereof are omitted here. 
       FIG. 11  is a plan view of a cut pattern CP 5  according to an embodiment. 
     Referring to  FIG. 11 , the narrow pattern P 1  may include a plurality of islands (e.g., island patterns). Side surfaces of each of the islands may be surrounded by the cut pattern insulator P 2 . A dimension of each island in one direction (e.g., in the direction D 1 ) may be W 3 , and W 3  may be greater than W 1  (W 3 &gt;W 1 , see  FIG. 7B ). 
       FIG. 12  is a plan view of a cut pattern CP 6  according to an embodiment. 
     Referring to  FIG. 12 , the cut pattern CP 6  may denote a portion indicated by dashed lines. The cut pattern CP 6  may include the narrow patterns P 1  extending in one direction. Some of the narrow patterns P 1  may be connected to the first ground selection line GSL 1 . Some other of the narrow patterns P 1  may be connected to the second ground selection line GSL 2 . As shown in FIG.  12 , since none of the narrow patterns P 1  is connected to both the first ground selection line GSL 1  and the second ground selection line GSL 2 , the first ground selection line GSL 1  and the second ground selection line GSL 2  may be electrically insulated from each other. 
     Also, the cut pattern insulator P 2  may extend in a zig-zag shape along the narrow patterns P 1 . 
       FIG. 13  is a plan view of a cut pattern CP 7  according to an embodiment. 
     Referring to  FIG. 13 , there may be only one narrow pattern P 1  in the cut pattern CP 7 . The narrow pattern P 1  may be surrounded by the cut pattern insulator P 2 . The cut pattern insulator P 2  may extend along a closed perimeter of the cut pattern CP 7 . For example, the narrow pattern P 1  may have a continuously formed pattern, e.g., a square pattern or a rectangular pattern, and the cut pattern insulator P 2  may surround the narrow pattern P 1 , e.g., in a plan view. 
     In  FIG. 13 , an example in which the isolation region  121  does not meet the narrow pattern P 1  is shown, but in certain embodiments, the isolation region  121  may farther extend to meet the narrow pattern P 1 . 
       FIG. 14  is a plan view of a cut pattern CP 8  according to an embodiment. 
     Referring to  FIG. 14 , the cut pattern CP 8  may denote a portion indicated by dashed lines. The narrow pattern P 1  may include first narrow patterns P 11  respectively connected to the first ground selection line GSL 1  and the second ground selection line GSL 2 , and second narrow patterns P 12  that are not connected to the first and second ground selection lines GSL 1  and GSL 2 . 
     The first narrow patterns P 11  and the second narrow patterns P 12  may respectively extend in one direction (here, the direction D 1 ) in parallel with each other. The second narrow patterns P 12  may be surrounded by the cut pattern insulator P 2 , e.g., in a plan view. The first narrow patterns P 11  may be surrounded, e.g., in a plan view, by the cut pattern insulator P 2 , except for portions connected to the first and second ground selection lines GSL 1  and GSL 2 . 
     The semiconductor memory device and the semiconductor device may maintain a high operation speed with high reliability and may be manufactured at reduced cost. 
       FIGS. 15A to 15J  are cross-sectional views for describing a method of manufacturing a semiconductor memory device in order, according to an embodiment. In  FIGS. 15A to 15J , cross-sections A-A′ and B-B′ are taken along lines A-A′ and B-B′ of  FIG. 5 , respectively. 
     Referring to  FIG. 15A , a substrate  110  is provided. The substrate  110  may include Si, Ge, or SiGe. In some embodiments, the substrate  110  may include a silicon-on-insulator (SOI) substrate or a germanium-on-insulator (GeOI) substrate. The substrate  110  may be of a first conductive type, for example, of a P type. 
     A buffer dielectric film  122  may be provided on the substrate  110 . The buffer dielectric film  122  may include, for example, a silicon oxide film. The buffer dielectric film  122  may be formed by, for example, a thermal oxidation process. In some embodiments, the buffer dielectric film  122  may include a middle temperature oxide (MTO). 
     A sacrificial layer  123 , which may be used later to form a ground selection line GSL, may be provided on the buffer dielectric film  122 . The sacrificial layer  123  may include a material having different wet-etching characteristics than the buffer dielectric film  122  and an insulating layer  124  formed on the sacrificial layer  123  (see  FIG. 15B , which will be described later). The sacrificial layer  123  may include, for example, a silicon nitride layer, a silicon oxynitride layer, a polysilicon layer, or a polysilicon germanium layer. The sacrificial layer  123  may be formed by, for example, a CVD method. 
     The sacrificial layer  123  and the buffer dielectric film  122  may be at least partially removed from a bridge region BRR. For example, the bridge region BRR may be a region in which a bridge pattern or bridge patterns are formed. For example, the bridge region BRR may include a portion of substrate  110  on which the bridge pattern(s) are formed. In some embodiments, the buffer dielectric film  122  and the sacrificial layer  123  may be partially removed from the bridge region BRR to pattern narrow patterns P 1  of a desired shape. A photolithography process may be used to selectively pattern the buffer dielectric film  122  and the sacrificial layer  123  in the bridge region BRR. 
     The narrow patterns P 1  provided in the bridge region BRR may be any one of the narrow patterns P 1  shown in  FIGS. 7A to 14 . 
     Referring to  FIG. 15B , the cut pattern insulator P 2  may be formed in the space between the narrow patterns P 1 . The cut pattern insulator P 2  may be formed by an ALD process. As well known in the art, since the ALD process has superior step coverage to other deposition methods, the cut pattern insulator P 2  may be formed with excellent conformity. 
     As described above with reference to  FIGS. 7A to 14 , the horizontal dimension of an empty space between the narrow patterns P 1  may be relatively small in at least one direction, and thus the space may be rapidly filled by the ALD process. Also, the cut pattern insulator P 2  may be formed with excellent conformity, and thus may cover an upper surface of the sacrificial layer  123 , as well as upper surfaces of the narrow patterns P 1 , to obtain the first insulating layer  124   a . The first insulating layer  124   a  may have a substantially flat upper surface. The first insulating layer  124   a  may have a substantially flat upper surface because the cut pattern insulator P 2  and the first insulating layer  124   a  are formed with high conformity by the ALD process. 
     The insulating layer  124  may be formed on the first insulating layer  124   a . The insulating layer  124  may be formed by a method other than the ALD process. For example, the cut pattern insulator P 2  and the first insulating layer  124   a  may include silicon oxide layers formed by the ALD process, and the insulating layer  124  may include, but is not limited to, a tetraethyl orthosilicate (TEOS) oxide using TEOS as a silicon source, a high density plasma (HDP) oxide formed by using silane as a silicon source and using the HDP, etc. 
     In some embodiments, there may be an interface between the first insulating layer  124   a  and the insulating layer  124 . 
     Referring to  FIG. 15C , sacrificial layers  123  and insulating layers  124  are alternately stacked. A thickness of an uppermost insulating layer  124  may be greater than those of other insulating layers  124 . The insulating layers  124  may include, for example, a TEOS oxide or HDP oxide layer. The sacrificial layers  123  may include a material having different wet-etching characteristics, e.g., etching selectivity, than the buffer dielectric film  122  and the insulating layers  124 . The sacrificial layers  123  may include, for example, a silicon nitride layer, a silicon oxynitride layer, a polysilicon layer, or a polysilicon germanium layer. The sacrificial layers  123  and the insulating layers  124  may be formed by, for example, a CVD method. 
     When the sacrificial layers  123  and the insulating layers  124  are stacked without forming the cut pattern CP in the bridge region BRR (e.g., below the bridges BG), dented portions (e.g., in the bridges BG as shown in  FIG. 16 ) may be accumulated, which may cause product failure such as breakdown, because an electric field may concentrate on an upper portion of the bridge region BRR in horizontal electrodes that will be formed later. 
       FIG. 16  shows a cross-section of a bridge region including bridges BG connecting word lines when the ground selection line GSL and the word lines WL 0 , WL 1 , and WL 2  are formed without forming the cut pattern CP. 
     Referring to  FIG. 16 , in a region (denoted by a dashed rectangle) where the ground selection line GSL is disconnected, the word lines WL 0 , WL 1 , and WL 2  stacked on the region and insulators therebetween may have a dented cross-sectional shape. In such a semiconductor device, an electric field may concentrate on the dented portion (denoted by a solid-line rectangle) during operation, and thus, failure such as a breakdown may occur. 
     Referring to  FIG. 15D , cell holes H are formed to penetrate through the buffer dielectric film  122 , the sacrificial layers  123 , and the insulating layers  124  to expose the substrate  110 . The cell holes H may be formed by, for example, a photolithography process. 
     Referring to  FIGS. 15E and 15F , cell columns PL may be formed in the cell holes H. A process of forming the cell columns PL will be described below in more detail with reference to  FIGS. 17A and 17B , which are enlarged views of regions C in  FIGS. 15E and 15F , respectively. 
     Referring to  FIGS. 15E and 17A , a protective layer  131  may be formed on a sidewall of each of the cell holes H. The protective layer  131  may include a silicon oxide layer. A charge storage layer  133  is provided on the protective layer  131 . The charge storage layer  133  may include a charge trap layer or an insulating layer including conductive nano-particles. The charge trap layer may include, for example, a silicon nitride layer. A tunnel insulating layer  132  is provided on the charge storage layer  133 . The tunnel insulating layer  132  may include a silicon oxide layer. The protective layer  131 , the tunnel insulating layer  132 , and the charge storage layer  133  may be formed by an ALD or a CVD method. 
     A first sub-semiconductor layer  135   a  may be provided on the tunnel insulating layer  132 . The first sub-semiconductor layer  135   a  may be anisotropically etched to expose the substrate  110 . The first sub-semiconductor layer  135   a  may remain as a spacer layer on the sidewall of the tunnel insulating layer  132 . A second sub-semiconductor layer  135   b  may be provided on the first sub-semiconductor layer  135   a . The second sub-semiconductor layer  135   b  contacts the substrate  110 . The first and second sub-semiconductor layers  135   a  and  135   b  may be formed by an ALD or CVD method. The first and second sub-semiconductor layers  135   a  and  135   b  may include amorphous silicon layers. 
     Referring to  FIGS. 15F and 17B , a thermal treatment process is performed, and the first and second sub-semiconductor layers  135   a  and  135   b  may be changed into a semiconductor layer  135 . The semiconductor layer  135  may include a polysilicon layer or a crystalline silicon layer. 
     The semiconductor layer  135  does not completely fill the cell holes H, but an insulating material may be provided on the semiconductor layer  135  to completely fill the cell holes H. The semiconductor layer  135  and the insulating material may be planarized to expose an uppermost insulating layer  124 . Accordingly, cylindrical cell columns PL filled with a filling insulating layer  137  may be formed. The semiconductor columns PL may include semiconductor layers of a first conductive type. Unlike  FIGS. 15F and 17B , the semiconductor layer may be formed to fully fill the cell holes H in certain embodiments. In this case, there is no need to form the filling insulating layer  137 . 
     Upper portions of the cell columns PL may be recessed to be lower than the uppermost insulating layer  124 . A conductive pattern  136  may be formed in the recessed upper portion of each of the cell columns PL in the cell holes H. The conductive patterns  136  may include doped polysilicon or metal. Impurity ions of a second conductive type may be implanted into upper portions of the conductive pattern  136  and the cell columns PL to form drain regions D. The second conductive type may be, for example, an N-type. 
     Referring to  FIG. 15G , the buffer dielectric film  122 , the sacrificial layers  123 , and the insulating layers  124  may be continuously patterned to form isolation regions  121  that extend in a first direction D 1  and are separated from one another to partially expose the substrate  110 . As a result of the patterning, insulating patterns  125  may be formed from the insulating layers  124 . Due to the patterning, an edge of the cut pattern CP may be partially removed. As a result, sacrificial layers  123  may be removed from regions where the ground selection lines GSL are to be formed. 
     Prior to the patterning, the uppermost insulating layer  124  and the sacrificial layer  123  between the isolation regions  121  may be patterned to form an opening  127 . The opening  127  may extend between the isolation regions  121  in the first direction D 1  to thereby divide the uppermost sacrificial layer  123  into two. The opening  127  may be filled with an insulating layer, for example, a silicon oxide layer. 
     Referring to  FIG. 15H , the sacrificial layers  123  exposed by the isolation regions  121  may be selectively removed to form recess regions  126 . The recess regions  126 , as regions from which the sacrificial layers  123  are removed, may be defined by the cell columns PL and the insulating patterns  125 . When the sacrificial layers  123  include a silicon nitride layer or a silicon oxynitride layer, the sacrificial layers  123  may be removed using an etchant including phosphoric acid. A side wall of the cell columns PL may be partially exposed through the recess regions  126 . 
     The protective layer  131  may prevent damage to the charge storage layer  133  caused by an etchant used to remove the sacrificial layers  123 . Portions of the protective layer  131  exposed by the recess regions  126  may be selectively removed. When the protective layer  131  includes a silicon oxide layer, the protective layer  131  may be removed by, for example, an etchant including fluoric acid. For example, a portion of the charge storage layer  133  may be exposed through the recess regions  126 . 
     To make formation of the cell holes H easier, a total height of the stack of the sacrificial layers  123  and the insulating layers  124  may be reduced. Accordingly, the cell holes H may have a reduced aspect ratio, which may facilitate etching the stack of the sacrificial layers  123  and the insulating layers  124 . When the number of stacked layers is the same, the total height of the stack may be reduced by reducing the thickness of each of the sacrificial layers  123  and/or the thickness of each of the insulating layers  124 . 
     Referring to  FIG. 15I , a blocking dielectric layer  134  may be formed in the recess regions  126 . The blocking dielectric layer  134  may be conformally formed on upper and lower surfaces of the insulating patterns  125  and on the charge storage layer  133  exposed in the recess regions  126 . The blocking dielectric layer  134  may include a high-k dielectric layer, for example, an aluminum oxide layer or a hafnium oxide layer. The blocking dielectric layer  134  may have a multilayer structure including a plurality of thin layers. For example, the blocking dielectric layer  134  may include an aluminum oxide layer and a silicon oxide layer, wherein the aluminum oxide layer and the silicon oxide layer may be stacked in any of a variety of stacking orders. The blocking dielectric layer  134  may be formed by ALD and/or CVD with a good step coverage. 
     Subsequently, a conductive layer  140  may be formed on the blocking dielectric layer  134 . The conductive layer  140  may include at least one of a doped silicon layer, a metal layer, a metal nitride layer, and a metal silicide layer. The conductive layer  140  may be formed by CVD or ALD. For example, the conductive layer  140  may include a barrier layer, and a metal layer on the barrier layer. The barrier layer may be a metal nitride layer, for example, a titanium nitride layer. The metal layer may be, for example, a tungsten layer. As another example, the conductive layer  140  may include a polysilicon layer, and a silicide layer on the polysilicon layer. In this case, the conductive layer  140  may be formed by forming a polysilicon layer, removing portions of the polysilicon layer adjacent to the isolation region  121  to form recesses in the polysilicon layer, forming a metal layer on the polysilicon layer having the recesses, thermally treating the metal layer to form a silicide layer, and removing an unreacted portion of the metal layer. The metal layer used to form the silicide layer may include tungsten, titanium, cobalt, or nickel. 
       FIG. 17C  is an enlarged view of part C of  FIG. 15I  in detail. 
     Referring to  FIG. 17C , only the blocking dielectric layer  134  may be formed in the recess regions  126 , whereas the tunnel insulating layer  132  and the charge storage layer  133  may be formed in the cell holes H. 
     In some embodiments, all the tunnel insulating layer  132 , the charge storage layer  133 , and the blocking dielectric layer  134 , which may constitute the data storage element  130 , may be formed in the recess regions  126  (see  FIG. 15H ). In this case, the protective layer  131  may not be formed. For example, in the processes of  FIGS. 15E and 15F , the cell columns PL may be formed without forming the protective layer  131 , the charge storage layer  133 , and the tunnel insulating layer  132  in the cell holes H. The cell columns PL may be formed by depositing a semiconductor layer  135  in the cell holes H. In some embodiments, the filling insulating layer  137  may be formed at the center of the semiconductor layer  135  similarly to the ones shown in  FIGS. 15F and 15G . Then, in the process of  FIG. 15I , the tunnel insulating layer  132 , the charge storage layer  133 , and the blocking dielectric layer  134  may be sequentially formed in the recess regions  126 . Next, the conductive layer  140  may be formed on the blocking dielectric layer  134 . 
     In some embodiments, the charge storage layer  133  and the blocking dielectric layer  134  may be formed in the recess regions  126 . In the processes of  FIGS. 15E and 15F , after the protective layer  131  and the tunnel insulating layer  132  are formed in the cell holes H, the cell columns PL may be formed. The cell columns PL may be formed in a similar manner as in the processes of  FIGS. 15E and 15F . Then, in the process of  FIG. 15I , the charge storage layer  133  and the blocking dielectric layer  134  may be sequentially formed in the recess regions  126 . Next, the conductive layer  140  may be formed on the blocking dielectric layer  134 . 
     In some embodiments, all the tunnel insulating layer  132 , the charge storage layer  133 , and the blocking dielectric layer  134 , which may constitute the data storage element  130 , may be formed in the cell holes H. In the processes of  FIGS. 15E and 15F , the protective layer  131 , the blocking dielectric layer  134 , the charge storage layer  133 , and the tunnel insulating layer  132  may be sequentially formed in the cell holes H. The cell columns PL may be formed on the tunnel insulating layer  132 . The cell columns PL may be formed in a similar manner as in the processes of  FIGS. 15E and 15F . Next, in the process of  FIG. 15I , the conductive layer  140  may be formed in the recess regions  126 . 
     In some embodiments, the data storage element  130  may be a variable resistance pattern. The variable resistance pattern may include at least one of materials having variable resistance characteristics. 
     For example, the data storage element  130  may include a material (for example, a phase change material) having an electrical resistance that may be changed by heat generated by an electric current that passes through an adjacent electrode. The phase change material may include at least one of antimony (Sb), tellurium (Te), and selenium (Se). For example, the phase change material may include about 20 Atom % to about 80 Atom % of tellurium (Te), about 5 Atom % to about 50 Atom % of antimony (Sb), and the balance of germanium (Ge) as a chalcogen compound. The phase change material may further include at least one of N, O, C, Bi, In, B, Sn, Si, Ti, Al, Ni, Fe, Dy, and La as impurities. Alternatively, the variable resistance pattern may be formed of one of GeBiTe, InSb, GeSb, and GaSb. 
     In some embodiments, the data storage element  130  may have a thin-film structure having a variable electrical resistance that may be changed due to spin transfer by an electric field that passes through the thin-film structure. The data storage element  130  may have a thin-film structure having magnetoresistance characteristics, and may include, for example, at least one ferromagnetic material and/or at least one antiferromagnetic material. 
     As another example, the data storage element  130  may include at least one of a perovskite compound and/or a transition metal oxide. For example, the data storage element  130  may include at least one of niobium oxide, titanium oxide, nickel oxide, zirconium oxide, vanadium oxide, PCMO ((Pr,Ca)MnO 3 ), strontium-titanium oxide, barium-strontium-titanium oxide, strontium-zirconium oxide, barium-zirconium oxide, and barium-strontium-zirconium oxide. 
     In these embodiments, the cell columns PL may be conductive columns. For example, the cell columns PL may include a conductive material. The conductive material may include, for example, at least one of a doped semiconductor, a metal, a conductive metal nitride, a silicide, and a nano structure such as carbon nanotubes or graphene. 
     To implement this structures, in the processes of  FIGS. 15E and 15F , the protective layer  131  and the data storage element  130  may be sequentially formed in the cell holes H. The cell columns PL may be formed on the data storage element  130 . The cell columns PL may be formed by depositing a conductive material. Next, in the process of  FIG. 15I , the conductive layer  140  may be formed in the recess regions  126 . 
     Subsequently, referring to  FIG. 15J , a portion of the conductive layer  140  formed outside the recess regions  26  may be removed. Accordingly, horizontal electrodes are formed in the recess regions  126 . The horizontal electrodes may include the ground selection line GSL, the word lines WL 0  to WL 3 , the dummy word lines DM 1  and DM 2 , and the string selection lines SSL 1  and SSL 2 . For example, portions of each of the string selection lines SSL 1  and SSL 2 , dummy word lines DM 1  and DM 2 , word lines WL 0 -WL 3 , and ground selection line GSL may be gate electrodes of corresponding transistors. The upper string selection lines SSL 1  and SSL 2  may extend in the first direction D 1 , and each of the string selection lines SSL 1  and SSL 2  may be divided into two in the second direction D 2 . For example, the opening  127  and the insulating layer formed in the opening  127  may divide each of the string selection lines SSL 1  and SSL 2  into two separated string selection lines corresponding to one word line stack. For example, one word line stack may include two string selection lines disposed at the same vertical level. For example, one word line stack may include four string selection lines formed in two layers, each of which includes two parallel string selection lines. 
     As the portion of the conductive layer  140  formed in the isolation regions  121  is removed, a corresponding region of the substrate  110  may be exposed. A high concentration of impurity ions may be provided into the exposed region of the substrate  110  to form the common source lines CSL. 
     Then, an isolation insulating layer  120  that fills the isolation regions  121  may be formed. The cell columns PL arranged in the second direction D 2  may be connected in common to one upper wiring BL 1  or BL 2  (see  FIG. 3 ). 
       FIG. 18  is a cross-sectional view illustrating a cell column of a semiconductor memory device according to an embodiment. In the embodiment of  FIG. 18 , a channel contact region  151  is further formed in a bottom portion of cell holes H, unlike the embodiment illustrated in  FIG. 3 . In this embodiment, the differences from the embodiment of  FIG. 3  will be mainly described, and the same structure with the embodiment of  FIG. 3  may be omitted in the below description. 
     Referring to  FIG. 18 , after the cell holes H are formed as illustrated in  FIG. 15D , a channel contact region  151  may be formed on a region of the substrate  110  that is exposed through a bottom in each of the cell holes H. In some embodiments, the channel contact region  151  may be formed on the exposed region of the substrate  110  by selective epitaxial growth (SEG). An upper surface of the channel contact region  151  may be at a level higher than an upper surface of the lowermost sacrificial layer  123 . 
     Then, p-type impurities may be implanted into the channel contact region  151  by an ion implantation process. For example, the p-type impurities may be aluminum (Al), boron (B), indium (In), or potassium (K). A concentration of the p-type impurities may be about 5E16 to 1E19 atoms/cm 3 . In some other embodiments, the p-type impurities may be in-situ doped while growing the channel contact region  151  by SEG. 
     Subsequently, after the cell columns PL and the isolation regions  121  are formed as illustrated in  FIGS. 15E to 15G , the sacrificial layers  123  may be removed as illustrated in  FIG. 15H , and an auxiliary gate insulating layer  153  may be formed on a sidewall of the channel contact region  151  by a thermal oxidation process. The auxiliary gate insulating layer  153  may be a thermal oxidation layer formed by a thermal oxidation of a part of the channel contact region  151  grown by SEG. However, the thermal oxidation process for forming the auxiliary gate insulating layer  153  may be omitted. 
     Subsequently, after the blocking dielectric layer  134 , the tunnel insulating layer  132 , the charge storage layer  133 , and the conductive layer  140  are formed as illustrated in  FIGS. 15I and 15J , an isolation insulating layer  120  that fills each of the isolation regions  121  may be formed. For example, the isolation insulating layer  120  may form an isolation pattern in the isolation regions  121 . 
     The above-described methods and structures may be applied when an arbitrary upper layer having a flat upper surface is formed on a lower layer having a relatively large/deep recess pattern.  FIGS. 19A and 19B  are perspective views for describing a method of forming an upper layer  230  having a flat upper surface on an upper portion of a lower layer  220  having a relatively large recess pattern. 
     Referring to  FIG. 19A , the lower layer  220  may be provided on the substrate  110 , and may include an arbitrary material. For example, the lower layer  220  may include a semiconductor material, a metal material, an insulating material, an inorganic material, etc. The lower layer  220  may include a recess pattern RP. The lower layer  220  may further include narrow patterns P 1  having a fine width W 1  in the recess pattern RP. In some embodiments, the narrow pattern P 1  may include the same material as or a different material from that of the lower layer  220 . The narrow patterns P 1  may be arranged with sufficiently small intervals W 2 . 
     Referring to  FIG. 19B , the upper layer  230  may be formed on the lower layer  220  by a method capable of forming a highly conformal layer, e.g., the ALD. As described above with reference to  FIGS. 7A and 7B , when the interval between the narrow patterns P 1  is sufficiently small, e.g., about 3 nm to about 100 nm, a space between two narrow patterns P 1  may be rapidly filled by the upper layer  230  while the upper layer  230  is formed by the ALD. The upper layer  230  may have an even and flat upper surface due to the narrow patterns P 1 . For example, the narrow patterns P 1  may help cause the upper layer  230  to have a flat upper surface compared to a case where the narrow patterns P 1  are not formed in the recess pattern RP. 
     As described above, although the exemplary embodiments have been disclosed, one of ordinary skill in the art will appreciate that various modifications are possible, without departing from the scope and spirit of the inventive concept as disclosed in the accompanying claims. Therefore, all differences within the scope will be construed as being included in the inventive concept. 
     While the inventive concept has been particularly shown and described with reference to embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims.