Patent Publication Number: US-10332902-B2

Title: Three-dimensional semiconductor memory device including vertically stacked electrodes

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/348,009 filed Nov. 10, 2016, now U.S. Pat. No. 9,837.429, which is a continuation of U.S. application Ser. No. 14/878,453 filed on Oct. 8, 2015, issued as U.S. Pat. No. 9,515,087 on Dec. 6, 2016, which claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2014-0146296, filed on Oct. 27, 2014, in the Korean Intellectual. Property Office, the disclosures of which are incorporated by reference herein in their entireties. 
    
    
     TECHNICAL FIELD 
     Exemplary embodiments of the inventive concept relate to three-dimensional (3D) semiconductor memory devices. 
     DISCUSSION OF THE RELATED ART 
     Semiconductor devices are becoming more highly integrated to meet demands of high performance and low costs. The integration density of a semiconductor device directly affects its cost. For example, an integration degree of a two-dimensional (2D) or planar semiconductor device is mainly determined by an area needed for a unit memory cell. Therefore, the integration density of the 2D or planar semiconductor device depends on a technique used for fine pattern formation. Even finer patterns may be formed to increase the density of the 2D or planar semiconductor device. However, extremely advanced and high-priced equipment is needed to form the fine patterns. Accordingly, three-dimensional (3D) semiconductor memory devices including three-dimensionally arranged memory cells have been developed to increase integration density. 
     SUMMARY 
     Exemplary embodiments of the inventive concepts provide three-dimensional (3D) semiconductor memory devices with increased reliability and integration density. 
     In an exemplary embodiment of the inventive concept, a 3D semiconductor memory device may include: a peripheral logic structure including peripheral logic circuits disposed on a semiconductor substrate and a first insulation layer overlapping the peripheral logic circuits; and a plurality of memory blocks disposed on the peripheral logic structure and spaced apart from each other. At least one of the memory blocks may include: a well plate electrode; a semiconductor layer in contact with a first surface of the well plate electrode; a stack structure including a plurality of electrodes vertically stacked on the semiconductor layer; and a plurality of vertical structures penetrating the stack structure and connected to the semiconductor layer. 
     In an exemplary embodiment of the inventive concept, the stack structure may extend in a first direction on the semiconductor layer. The semiconductor layer may include a common source region disposed at a side of the stack structure. The common source region may have dopants of a first conductivity type. 
     In an exemplary embodiment of the inventive concept, the common source region may be spaced apart from the well plate electrode. 
     In an exemplary embodiment of the inventive concept, the peripheral logic circuits may include a voltage generator disposed on the semiconductor substrate, and the peripheral logic structure may further include: a first interconnection structure for electrically connecting the well plate electrode to the voltage generator. 
     In an exemplary embodiment of the inventive concept, the peripheral logic circuits may include a page buffer and a voltage generator that are disposed on the semiconductor substrate. The peripheral logic structure may further include: a plurality of first interconnections electrically connected to the page buffer; and a second interconnection electrically connected to the voltage generator. The second interconnection may be electrically connected to the well plate electrode. 
     In an exemplary embodiment of the inventive concept, the second interconnection may include a plurality of second interconnections. The second interconnections and the first interconnections may be disposed at the same level from a first surface of the semiconductor substrate, and the plurality of first interconnections may be arranged between the second interconnections spaced apart from each other. 
     In an exemplary embodiment of the inventive concept, the at least one memory block may further include: a plurality of third interconnections extending in parallel to each other on the stack structure. The third interconnections may be electrically connected to the first interconnections. 
     In an exemplary embodiment of the inventive concept, the semiconductor layer may have dopants of a second conductivity type. The semiconductor layer may include: a first portion in contact with the well plate electrode; and a second portion on the first portion. A concentration of the dopants of the second conductivity type in the first portion may be higher than a concentration of the dopants of the second conductivity type in the second portion. 
     In an exemplary embodiment of the inventive concept, the semiconductor layer may include a well dopant region that has a second conductivity type and is in contact with the well plate electrode. 
     In an exemplary embodiment of the inventive concept, the well plate electrode of the at least one memory block and a well plate electrode of another memory block may be spaced apart from each other on the first insulation layer. 
     In an exemplary embodiment of the inventive concept, an area of the well plate electrode may be substantially equal to an area of the semiconductor layer. 
     In an exemplary embodiment of the inventive concept, the 3D semiconductor memory device may further include: a data storage layer disposed between the stack structure and each of the vertical structures. 
     In an exemplary embodiment of the inventive concept, a 3D semiconductor memory device may include: a well plate electrode; a semiconductor layer overlapping a first surface of the well plate electrode; a plurality of stack structures extending in parallel to each other along a first direction on the semiconductor layer, first and second stack structures of the stack structures comprising a plurality of electrodes vertically stacked on the semiconductor layer; vertical structures penetrating the first and second stack structures and connected to the semiconductor layer; and common source regions formed in the semiconductor layer between the first and second stack structures, the common source regions having dopants of a first conductivity type. 
     In an exemplary embodiment of the inventive concept, the common source regions may be spaced apart from the first surface of the well plate electrode. 
     In an exemplary embodiment of the inventive concept, the semiconductor layer may include a well dopant region that has a second conductivity type and is in contact with the well plate electrode. 
     In an exemplary embodiment of the inventive concept, the semiconductor layer may have dopants of a second conductivity type. The semiconductor layer may include: a first portion in contact with the well plate electrode; and a second portion on the first portion. A concentration of the dopants of the second conductivity type in the first portion may be higher than a concentration of the dopants of the second conductivity type in the second portion. 
     In an exemplary embodiment of the inventive concept, an area of the well plate electrode may be substantially equal to an area of the semiconductor layer. 
     In an exemplary embodiment of the inventive concept, the 3D semiconductor memory device may further include: a peripheral logic structure including peripheral logic circuits formed on a semiconductor substrate and a first insulation layer overlapping the peripheral logic circuits. The well plate electrode may be disposed on the first insulation layer. 
     In an exemplary embodiment of the inventive concept, the peripheral logic circuits may include a voltage generator disposed on the semiconductor substrate and electrically connected to the well plate electrode. A vertical distance between the voltage generator and the well plate electrode may be smaller than vertical heights of the first and second stack structures. 
     In an exemplary embodiment of the inventive concept, the 3D semiconductor memory device may further include: a data storage layer disposed between the first and second stack structures and each of the vertical structures. 
     In an exemplary embodiment of the inventive concept, a 3D semiconductor memory device may include: a first logic circuit disposed on a semiconductor substrate; an insulating layer disposed on the at least one logic circuit and the semiconductor substrate; a well plate electrode disposed on the insulating layer and overlapping the first logic circuit; and a semiconductor layer disposed between the well plate electrode and a plurality of vertically stacked electrodes. 
     In an exemplary embodiment of the inventive concept, the well plate electrode may be in direct contact with a first surface of the semiconductor layer. 
     In an exemplary embodiment of the inventive concept, an entire first surface of the semiconductor layer may be in direct contact with the well plate electrode. 
     In an exemplary embodiment of the inventive concept, the first logic circuit may be a voltage generator or a page buffer. 
     In an exemplary embodiment of the inventive concept, the well plate electrode, the semiconductor layer and the vertically stacked electrodes may form a cell array structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the inventive concept will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: 
         FIG. 1  is a block diagram illustrating a three-dimensional (3D) semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 2  is a perspective view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 3  is a circuit diagram illustrating a cell array of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIGS. 4 and 5  are plan views each illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 6  is a plan view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 7  is a cross-sectional view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIGS. 8 and 9  are diagrams each illustrating an arrangement of peripheral logic circuits in a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 10  is a perspective view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 11  is a plan view illustrating a portion of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIGS. 12, 13, and 14  are cross-sectional views respectively taken along lines I-I′, II-II′, and III-III′ of  FIG. 11  to illustrate a portion of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIGS. 15A, 15B, 15C, and 15D  are enlarged views of a portion ‘A’ of  FIG. 12 , according to an exemplary embodiment of the inventive concept; 
         FIGS. 16A and 16B  are enlarged views of a portion ‘B’ of  FIG. 13 , according to an exemplary embodiment of the inventive concept; 
         FIGS. 17A, 17B, and 17C  are perspective views each illustrating peripheral logic structures of 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIGS. 18A and 18B  each illustrate a well plate electrode included in a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIGS. 19 and 20  are cross-sectional views respectively taken along lines I-I′ and II-II′ of  FIG. 11  to illustrate a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 21  is an enlarged view of a portion ‘B’ of  FIG. 20 , according to an exemplary embodiment of the inventive concept; 
         FIG. 22  is a view illustrating an erasing operation of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; 
         FIG. 23  is a block diagram illustrating an electronic system including a 3D semiconductor memory device according to an exemplary embodiments of the inventive concept; 
         FIG. 24  is a block diagram illustrating a memory card including a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept; and 
         FIG. 25  is a block diagram illustrating an information processing system including a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Exemplary embodiments of the inventive concept will now be described more fully hereinafter with reference to the accompanying drawings. The inventive concept, however, may be embodied in various forms and should not be construed as being limited to only the illustrated embodiments. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. 
     As used herein, the singular terms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element or intervening elements may be present. 
     It will be understood that when an element such as a layer, region or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present. 
     The same reference numerals or the same reference designators may denote the same elements throughout the specification. 
     Moreover, exemplary embodiments of the inventive concept are described herein with reference to cross-sectional illustrations and/or plane illustrations that are idealized examples. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments of the inventive concept should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etching region illustrated as a rectangle will, typically, have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the inventive concept. 
     Further, devices and methods of forming devices according to exemplary embodiments of the inventive concept described herein may be embodied in microelectronic devices such as integrated circuits. In this case, a plurality of devices according to exemplary embodiments of the inventive concept described herein may be integrated in the same microelectronic device. Accordingly, the cross-sectional view(s) illustrated herein may be replicated in two different directions, which need not be orthogonal, in the microelectronic device. Thus, a plan view of the microelectronic device that embodies devices according to exemplary embodiments of the inventive concept described herein may include a plurality of the devices in an array and/or in a two-dimensional pattern depending on the functionality of the microelectronic device. 
     The devices according to exemplary embodiments of the inventive concept described herein may be interspersed among other devices depending on the functionality of the microelectronic device. Moreover, microelectronic devices according to exemplary embodiments of the inventive concept described herein may be replicated in a third direction that may be orthogonal to the two different directions, to provide three-dimensional integrated circuits. 
     Accordingly, the cross-sectional view(s) illustrated herein provide support for a plurality of devices according to exemplary embodiments of the inventive concept described herein that extend along two different directions in a plan view and/or in three different directions in a perspective view. For example, when a single active region is illustrated in a cross-sectional view of a device/structure, the device/structure may include a plurality of active regions and transistor structures (or memory cell structures, gate structures, etc.) thereon, as would be illustrated by a plan view of the device/structure. 
       FIG. 1  is a block diagram illustrating a three-dimensional (3D) semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 1 , the 3D semiconductor memory device may include a memory cell array  1 , a row decoder  2 , a page buffer  3 , a column decoder  4 , and control circuits  5 . 
     The memory cell array  1  may include a plurality of memory blocks BLK 0  to BLKn. Each of the memory blocks BLK 0  to BLKn may include a plurality of memory cells, a plurality of word lines, and a plurality of bit lines. The word lines and the bit lines may be electrically connected to the memory cells. 
     The row decoder  2  may decode an address signal inputted from an external system to select one of the word lines. The address signal decoded by the row decoder  2  may be provided to a row driver. The row driver may provide word line voltages generated from a voltage generation circuit to the selected word line and unselected word lines in response to a control signal of the control circuits  5 . The row decoder  2  may be connected in common to the plurality of memory blocks BLK 0  to BLKn and may provide driving signals to the word lines of a memory block selected by a block selection signal. 
     The page buffer  3  may be connected to the memory cell array  1  through the bit lines to read data stored in the memory cells. The page buffer  3  may be connected to a selected bit line in response to an address signal decoded by the column decoder  4 . According to an operation mode, the page buffer  3  may temporarily store data to be stored in the memory cells or may sense data stored in the memory cells. For example, the page buffer  3  may be operated as a write driver during a program operation mode and may be operated as a sense amplifier during a read operation mode. The page buffer  3  may receive a power (e.g., a voltage or a current) from the control circuits  5  and may provide the received power to the selected bit line. 
     The column decoder  4  may provide a data-transmitting path between the page buffer  3  and an external device (e.g., a memory controller). The column decoder  4  may decode an inputted address signal to select one of the bit lines. The column decoder  4  may be connected in common to the plurality of memory blocks BLK 0  to BLKn and may provide data to the bit lines of the memory block selected by the block selection signal. 
     The control circuits  5  may control overall operations of the 3D semiconductor memory device. The control circuits  5  may receive control signals and an external voltage and may be operated in response to the received control signals. The control circuits  5  may include a voltage generator that generates voltages (e.g., a program voltage, a read voltage, and an erase voltage) used for internal operations by way of the external voltage. The control circuits  5  may control a read operation, a write operation, and/or an erase operation in response to the control signals. 
       FIG. 2  is a perspective view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 2 , the 3D semiconductor memory device may include a peripheral logic structure PS and a cell array structure CS. The cell array structure CS may be stacked on the peripheral logic structure PS. In other words, the cell array structure CS may overlap the peripheral logic structure PS when viewed from a plan view. 
     In an exemplary embodiment of the inventive concept, the peripheral logic structure PS may include the row and column decoders  2  and  4 , the page buffer  3  and the control circuits  5  which are described with reference to  FIG. 1 . The cell array structure CS may include a plurality of memory blocks BLK 0  to BLKn. Each of the memory blocks BLK 0  to BLKn may correspond to a data-erasing unit. The memory blocks BLK 0  to BLKn may include structures stacked on a plane extending in first and second directions D 1  and D 2 . The structures may be stacked along a third direction D 3  on the plane. Each of the memory blocks BLK 0  to BLKn may include a cell array having a 3D structure (or a vertical structure). The cell array may include a plurality of three-dimensionally arranged memory cells, a plurality of word lines, and a plurality of bit lines. The word lines and the bit lines may be connected to the three-dimensionally arranged memory cells. 
       FIG. 3  is a circuit diagram illustrating a cell array of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 3 , the cell array may include a common source line CSL, a plurality of bit lines BL, and a plurality of cell strings CSTR disposed between the common source line CSL and the bit lines BL. 
     The bit lines BL may be two-dimensionally arranged. A plurality of the cell strings CSTR may be connected in parallel to each of the bit lines BL. The cell strings CSTR may be connected in common to the common source line CSL. In other words, a plurality of the cell strings CSTR may be disposed between a common source line CSL and the plurality of bit lines BL. In an exemplary embodiment of the inventive concept, the common source line CSL may be provided in plural, and the plurality of common source lines CSL may be two-dimensionally arranged. The same voltage may be applied to the plurality of the common source lines CSL. Additionally, the plurality of common source lines CSL may be electrically controlled independently of each other. 
     Each of the cell strings CSTR may include a ground selection transistor GST connected to the common source line CSL, a string selection transistor SST connected to the bit line BL, and a plurality of memory cell transistors MCT interposed between the ground and string selection transistors GST and SST. The ground selection transistor GST, the memory cell transistors MCT and the string selection transistor SST may be connected in series to each other. 
     The common source line CSL may be connected in common to sources of the ground selection transistors GST. A ground selection line GSL, a plurality of word lines WL 0  to WL 3  and a string selection line SSL which are disposed between the common source line CSL and the bit lines BL may be used as gate electrodes of the ground selection transistor GST, the memory cell transistors MCT and the string selection transistor SST, respectively. The ground selection line GSL and the string selection line SSL may be provided in plural. Each of the memory cell transistors MCT may include a data storage element. 
       FIGS. 4 and 5  are plan views each illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIGS. 4 and 5 , row and column decoders  2  and  4 , the page buffer  3 , and control circuits  5  which constitute the peripheral logic structure (PS of  FIG. 2 ) may be disposed on a semiconductor substrate  10 . According to an exemplary embodiment of the inventive concept, the cell array structure (CS of  FIG. 2 ) including a cell array  1  (CAR) may be disposed on the page buffer  3  and the control circuits  5 . For example, as illustrated in  FIG. 4 , the page buffer  3  and the control circuits  5  may overlap the cell array  1 , and the row and column decoders  2  and  4  may be disposed around the cell array  1  when viewed from a plan view. In an exemplary embodiment of the inventive concept, as illustrated in  FIG. 5 , the column decoder  4 , the page buffer  3 , and the control circuits  5  may overlap the cell array  1  when viewed from a plan view. In this case, the row decoders  2  may be disposed around the cell array  1  when viewed from a plan view. 
       FIG. 6  is a plan view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept.  FIG. 7  is a cross-sectional view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept.  FIGS. 8 and 9  are diagrams each illustrating an arrangement of peripheral logic circuits in a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIGS. 6 and 7 , the peripheral logic structure PS and the cell array structure CS may be sequentially stacked on the semiconductor substrate  10 . In other words, the peripheral logic structure PS may be disposed between the semiconductor substrate  10  and the cell array structure CS in a vertical view. The peripheral logic structure PS and the cell array structure CS may overlap each other in a plan view. 
     In an exemplary embodiment of the inventive concept, the semiconductor substrate  10  may be a silicon substrate, a silicon-germanium substrate, a germanium substrate, or a single-crystalline epitaxial layer grown on a single-crystalline silicon substrate. 
     According to an exemplary embodiment of the inventive concept, the peripheral logic structure PS may include peripheral logic circuits integrated on the semiconductor substrate  10  and a lower insulation layer  50  covering the peripheral logic circuits. For example, the peripheral logic circuits may include the row and column decoders  2  and  4 , the page buffer  3  and the control circuits  5  described with reference to  FIGS. 1 and 4 . According to an exemplary embodiment of the inventive concept, a page buffer  20  and a voltage generator  30  may be disposed under the cell array structure CS and may be electrically connected to the cell array structure CS. 
     In an exemplary embodiment of the inventive concept, the cell array structure CS may be stacked on the peripheral logic structure PS and may include a plurality of memory blocks BLK 1  and BLK 2 . Each of the memory blocks BLK 1  and BLK 2  may include a well plate electrode  60 , a semiconductor layer  70 , and a stack structure ST. 
     The well plate electrode  60  may be disposed on the peripheral logic structure PS and may have a plate shape. The well plate electrode  60  may be disposed on a top surface of the lower insulation layer  50 . In an exemplary embodiment of the inventive concept, the well plate electrodes  60  of the memory blocks BLK 1  and BLK 2  may be spaced apart from each other. The well plate electrode  60  may be electrically connected to the voltage generator  30  of the peripheral logic structure PS. The well plate electrode  60  may include a metal (e.g., tungsten, copper, or aluminum), a conductive metal nitride (e.g., titanium nitride or tantalum nitride), a transition metal (e.g., titanium or tantalum), and/or a metal silicide layer. According to an exemplary embodiment of the inventive concept, an erase voltage generated by the voltage generator  30  may be applied to the well plate electrode  60  during an erase operation of the 3D semiconductor memory device. 
     The semiconductor layer  70  may be in direct contact with a top surface of the well plate electrode  60  and may cover an entire top surface of the well plate electrode  60 . The semiconductor layer  70  may include silicon (Si), germanium (Ge), or a mixture thereof. The semiconductor layer  70  may be formed of a semiconductor material doped with dopants having a first conductivity type or an intrinsic semiconductor material not doped with dopants. In addition, the semiconductor layer  70  may have a single-crystalline structure, an amorphous structure, or a poly-crystalline structure. 
     The stack structure ST may include electrodes EL sequentially stacked on the semiconductor layer  70 . The electrodes EL may form memory cells. Each of the electrodes EL may be formed of a conductive material (e.g., doped silicon or a metal) and may have a line shape or a plate shape. 
     According to an exemplary embodiment of the inventive concept, as illustrated in  FIG. 8 , the page buffer  20  may be disposed under each of the memory blocks BLK 1  and BLK 2  and the voltage generator  30  may be disposed under a plurality of the memory blocks BLK 1  and BLK 2 . In addition, a row decoder  15  may be disposed at a side of the memory blocks BLK 1  and BLK 2  when viewed from a plan view. According to an exemplary embodiment of the inventive concept, as illustrated in  FIG. 9 , the page buffer  20  and the voltage generator  30  may be disposed under each of the memory blocks BLK 1  and BLK 2  when viewed from a plan view. In addition, the row decoders  15  may be disposed at sides of the memory blocks BLK 1  and BLK 2  and between the memory blocks BLK 1  and BLK 2 . In an exemplary embodiment of the inventive concept, the voltage generator  30  may generate voltages (e.g., a program voltage, a read voltage, and an erase voltage) used for internal operations of the 3D semiconductor memory device. The voltage generator  30  may provide the generated erase voltage to the well plate electrode  60  of a selected one of the memory blocks BLK 1  and BLK 2 . 
       FIG. 10  is a perspective view illustrating a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept.  FIG. 11  is a plan view illustrating a portion of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept.  FIGS. 12 to 14  are cross-sectional views respectively taken along lines I-I′, II-II′, and III-III′ of  FIG. 11  to illustrate a portion of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIGS. 10 to 14 , a cell array structure CS may be stacked on a peripheral logic structure PS. In other words, the cell array structure CS may overlap the peripheral logic structure PS when viewed from a plan view. 
     According to an exemplary embodiment of the inventive concept, the peripheral logic structure PS may include peripheral logic circuits such as row and column decoders ( 2  and  4  of  FIG. 1 ), a page buffer ( 3  of  FIG. 1 ), and control circuits ( 5  of  FIG. 1 ). The peripheral logic circuits may be integrated on an entire top surface of a semiconductor substrate  10 . In addition, the peripheral logic structure PS may further include a lower interconnection structure electrically connected to the peripheral logic circuits and a lower insulation layer  50  covering the peripheral logic circuits and the lower interconnection structure. 
     According to an exemplary embodiment of the inventive concept, the peripheral logic structure PS may include first and second metal-oxide-semiconductor (MOS) transistors TR 1  and TR 2  included in a page buffer  20 , a third MOS transistor TR 3  included in a voltage generator  30 , and a fourth MOS transistor TR 4  included in a row decoder  40 . 
     The first MOS transistor TR 1  may be formed on a first well region  21   n  that is formed by doping a portion of the semiconductor substrate  10  with N-type dopants. The second MOS transistor TR 2  may be formed on a second well region  21   p  that is formed by doping a portion of the semiconductor substrate  10  with P-type dopants. The third MOS transistor TR 3  may be formed on a third well region  31  that is formed by doping a portion of the semiconductor substrate  10  with N-type or P-type dopants. The fourth MOS transistor TR 4  may be formed on a fourth well region  39  that is formed by doping a portion of the semiconductor substrate  10  with N-type or P-type dopants. Active regions may be defined in the first to fourth well regions  21   n ,  21   p ,  31 , and  39  by a device isolation layer  11 , respectively. In addition, contact plugs and interconnections that are electrically connected to the lower interconnection structure may be connected to the first to fourth MOS transistors TR 1 , TR 2 , TR 3 , and TR 4 . For example, such connections may be made to source and/or drain electrodes of the first to fourth MOS transistors TR 1 , TR 2 , TR 3 , and TR 4 . In detail, as shown in  FIG. 12 , MOS transistor TR 3  may be connected to a linking interconnection  41  via two contact plugs and an interconnection disposed between the two contact plugs. 
     According to an exemplary embodiment of the inventive concept, the lower interconnection structure may be disposed between the cell array structure CS and the peripheral logic circuits in a vertical view. The lower interconnection structure may include first lower interconnections  43 , the linking interconnection  41 , and second lower interconnections  45 . The first lower interconnections  43  may be electrically connected to the page buffer  20 . The linking interconnection  41  and the second lower interconnections  45  may be electrically connected to the voltage generator  30 . In addition, one or more well contact plugs WCP may be connected to the second lower interconnections  45 . Top surfaces of the well contact plugs WCP may be substantially coplanar with a top surface of the lower insulation layer  50 . 
     According to an exemplary embodiment of the inventive concept, the cell array structure CS may include a well plate electrode  60 , a semiconductor layer  70  covering the well plate electrode  60 , stack structures ST disposed on the semiconductor layer  70 , and vertical structures VS penetrating each of the stack structures ST. Each of the stack structures ST may include electrodes EL vertically stacked on the semiconductor layer  70 . 
     The well plate electrode  60  may be disposed on the top surface of the lower insulation layer  50  and may be in contact with the top surfaces of the well contact plugs WCP. In an exemplary embodiment of the inventive concept, the well plate electrode  60  may have a plate shape and may be electrically connected to the voltage generator  30  through the second lower interconnections  45  and the linking interconnection  41 . The well plate electrode  60  may include a metal (e.g., tungsten, copper, or aluminum), a conductive metal nitride (e.g., titanium nitride or tantalum nitride), a transition metal (e.g., titanium or tantalum), or a metal silicide. In an exemplary embodiment of the inventive concept, the well plate electrode  60  may be formed of the conductive metal nitride, and a thickness of the well plate electrode  60  may be less than that of the first and second lower interconnections  43  and  45 . 
     In an exemplary embodiment of the inventive concept, the well plate electrode  60  may overlap the second lower interconnections  45  when viewed from a plan view. Since the well plate electrode  60  has the plate shape, positions or arrangements of the well contact plugs WCP, the second lower interconnections  45 , the linking interconnection  41 , and the voltage generator  30  may be variously changed. This will be described later in more detail. 
     The semiconductor layer  70  may be in direct contact with a top surface of the well plate electrode  60 . In an exemplary embodiment of the inventive concept, an area of the semiconductor layer  70  may be substantially equal to an area of the well plate electrode  60 . The semiconductor layer  70  may include silicon (Si), germanium (Ge), or a mixture thereof. The semiconductor layer  70  may be formed of a semiconductor material doped with dopants having a first conductivity type or an intrinsic semiconductor material not doped with dopants. In addition, the semiconductor layer  70  may have a single-crystalline structure, an amorphous structure, or a poly-crystalline structure. In an exemplary embodiment of the inventive concept, the semiconductor layer  70  may include a cell array region CAR and a contact region CTR disposed around the cell array region CAR. 
     According to an exemplary embodiment of the inventive concept, a well conductive layer and a poly-silicon layer may be sequentially deposited on the lower insulation layer  50 , and the poly-silicon layer and the well conductive layer may be patterned to form the well plate electrode  60  and the semiconductor layer  70 . In an exemplary embodiment of the inventive concept, the poly-silicon layer may be doped with dopants having the first conductivity type during the process of depositing the poly-silicon layer. In an exemplary embodiment of the inventive concept, after an undoped poly-silicon layer is deposited, a lower portion of the semiconductor layer  70  may be doped with dopants having the first conductivity type to form a well dopant region. In an exemplary embodiment of the inventive concept, after the deposition of the poly-silicon layer, a laser annealing process may be performed to reduce a grain boundary of the poly-silicon layer. 
     According to an exemplary embodiment of the inventive concept, the stack structures ST may extend in parallel to each other in a first direction D 1  on the semiconductor layer  70  and may be spaced apart from each other in a second direction D 2 . Each of the stack structures ST may include the electrodes EL and insulating layers ILD that are alternately and repeatedly stacked on the semiconductor layer  70 . The electrodes EL of the stack structures ST may include a conductive material. For example, the electrodes EL may include a doped semiconductor material (e.g., doped silicon), a metal (e.g., tungsten, copper, or aluminum), a conductive metal nitride (e.g., titanium nitride or tantalum nitride), or a transition metal (e.g., titanium or tantalum). Thicknesses of the insulating layers ILD of the stack structures ST may be varied depending on characteristics of the 3D semiconductor memory device. For example, the thickness of the lowermost insulating layer ILD may be smaller than that of each of other insulating layers ILD. In addition, one or some of the insulating layers ILD may be thicker than other insulating layers ILD. The insulating layers ILD may include silicon oxide. 
     Each of the stack structures ST may have a stepwise structure in the contact region CTR to electrically connect the electrodes EL to the peripheral logic circuits. In other words, each of the stack structures ST may have a sloped profile in the contact region CTR. 
     An upper insulation layer  80  having a planarized top surface may be disposed on the semiconductor layer  70  to cover end portions of the electrodes EL which constitute the stepwise structure. In addition, a capping insulation layer  90  may cover a plurality of the stack structures ST and the upper insulation layer  80 . 
     Bit lines BL may be disposed on the capping insulation layer  90  to cross over the stack structures ST. The bit lines BL may extend in the second direction D 2 . The bit lines BL may be electrically connected to the vertical structures VS through bit line contact plugs BPLG. In addition, the bit lines BL may be electrically connected to the first lower interconnections  43  of the peripheral logic structure PS. 
     According to an exemplary embodiment of the inventive concept, the vertical structures VS may be disposed in the cell array region CAR and may penetrate the stack structures ST to be connected to the semiconductor layer  70 . In an exemplary embodiment of the inventive concept, the vertical structures VS may be arranged in a zigzag form along one direction when viewed from a plan view. In an exemplary embodiment of the inventive concept, the vertical structures VS may be arranged in a line along one direction when viewed from a plan view. In an exemplary embodiment of the inventive concept, the vertical structures VS may include a semiconductor material. Bottom surfaces of the vertical structures VS may be disposed at a level between the top surface and the bottom surface of the semiconductor layer  70 . Each of the vertical structures VS may include a contact pad connected to the bit line contact plug BPLG. The contact pad may correspond to a top end portion of the vertical structure VS. 
     According to an exemplary embodiment of the inventive concept, a data storage layer DS may be disposed between the stack structure ST and the vertical structure VS. In an exemplary embodiment of the inventive concept, the data storage layer DS may include a charge storage layer. For example, the data storage layer DS may include a trap insulating layer, a floating gate electrode, or an insulating layer including conductive nano dots. Data stored in the data storage layer DS may be changed using Fowler-Nordheim tunneling that is caused by a voltage difference between the electrode EL and the vertical structure VS including the semiconductor material. In an exemplary embodiment of the inventive concept, the data storage layer DS may include a thin layer capable of storing data on the basis of another operation principle. For example, the data storage layer DS may include a thin layer used in a phase-change memory or a thin layer used in a variable resistance memory. 
     In an exemplary embodiment of the inventive concept, each of common source regions  71  may be disposed in the semiconductor layer  70  between the stack structures ST adjacent to each other. The common source regions  71  may extend in parallel to the stack structures ST along the first direction D 1 . In an exemplary embodiment of the inventive concept, the common source regions  71  may be formed by injecting dopants having a second conductivity type into the semiconductor layer  70 . In an exemplary embodiment of the inventive concept, bottom surfaces of the common source regions  71  may be spaced apart from the top surface of the well plate electrode  60 . 
     According to an exemplary embodiment of the inventive concept, a common source plug CSPLG may be connected to each of the common source regions  71 . A sidewall insulating spacer SP may be disposed between the common source plug CSPLG and the stack structure ST. A ground voltage may be applied to the common source regions  71  through the common source plugs CSPLG during a read or program operation of the 3D semiconductor memory device. In an exemplary embodiment of the inventive concept, the common source plugs CSPLG may have substantially uniform widths and may extend in parallel to each other along the first direction D 1 . The sidewall insulating spacers SP may be opposite to each other between the stack structures ST adjacent to each other. In an exemplary embodiment of the inventive concept, the sidewall insulating spacer SP may fill a space between the stack structures ST adjacent to each other, and the common source plug CSPLG may penetrate the sidewall insulating spacer SP to be locally connected to the common source region  71 . 
     An interconnecting structure that electrically connects the cell array structure CS to the peripheral logic structure PS may be disposed on end portions, having the stepwise structures, of the stack structures ST. In an exemplary embodiment of the inventive concept, the interconnecting structure may include contact plugs PLG penetrating the upper insulation layer  80  to be respectively connected to the end portions of the electrodes EL, upper interconnections UCL disposed on the capping insulation layer  90  and connected to the contact plugs PLG through contact patterns CT, one or more connection plugs WPLG penetrating the capping insulation layer  90  and the upper and lower insulation layers  80  and  50 , and interconnection lines CL connecting the interconnection plugs WPLG to the upper interconnections UCL. 
     The contact plugs PLG disposed in the contact region CTR may have vertical lengths different from each other. Top surfaces of the contact plugs PLG may be substantially coplanar with the top surfaces of the vertical structures VS. 
     In an exemplary embodiment of the inventive concept, the stack structure ST and the peripheral logic structure PS may be electrically connected to each other through the interconnection plug WPLG. The interconnection plug WPLG may penetrate the capping insulating layer  90  and the upper and lower insulation layers  80  and  50  to be electrically connected to the peripheral logic circuit(s). For example, the interconnection plug WPLG may be electrically connected to the row decoder  40  (e.g., a word line driver). 
     During the erase operation of the 3D semiconductor memory device, the erase voltage may be provided to the semiconductor layer  70  and the vertical structures VS through the well plate electrode  60 . At this time, the erase voltage may be uniformly provided to the semiconductor layer  70  through the well plate electrode  60  having the plate shape. Thus, a time for providing the erase voltage to the two-dimensionally arranged vertical structures VS may be substantially uniform. In other words, the erase voltage can be prevented from being varied according to positions of the vertical structures VS. 
     In an exemplary embodiment of the inventive concept, a vertical distance between the well plate electrode  60  and the voltage generator  30  may be less than a height of the cell array structure CS. Thus, a transmitting path of the erase voltage from the voltage generator  30  to the well plate electrode  60  may be reduced. In other words, a voltage drop of the erase voltage may be reduced during the erase operation of the 3D semiconductor memory device. 
       FIGS. 15A, 15B, 15C, and 15D  are enlarged views of a portion ‘A’ of  FIG. 12 , according to an exemplary embodiment of the inventive concept. 
     According to an exemplary embodiment of the inventive concept, the 3D semiconductor memory device may be an NAND flash memory device. For example, the data storage layer DS disposed between the stack structure ST and the vertical structure VS may include a tunnel dielectric layer TIL, a charge storage layer CIL, and a blocking dielectric layer BLK. Data stored in the data storage layer DS may be changed using Fowler-Nordheim tunneling caused by the voltage difference between the electrode EL and the vertical structure VS including the semiconductor material. 
     According to an exemplary embodiment of the inventive concept illustrated in  FIG. 15A , the tunnel dielectric layer TIL, the charge storage layer CIL, and the blocking dielectric layer BLK may extend from between the vertical structure VS and the electrode EL to between the vertical structure VS and the insulating layer ILD. 
     According to an exemplary embodiment of the inventive concept illustrated in  FIG. 15B , the tunnel dielectric layer TIL and the charge storage layer CIL may extend from between the vertical structure VS and the electrode EL to between the vertical structure VS and the insulating layer ILD. The blocking dielectric layer BLK may extend from between the vertical structure VS and the electrode EL onto a top surface and a bottom surface of the electrode EL. In other words, the blocking dielectric layer BLK may be disposed between the electrode EL and the insulating layer ILD adjacent to each other. 
     According to an exemplary embodiment of the inventive concept illustrated in  FIG. 15C , the tunnel dielectric layer TIL may extend from between the vertical structure VS and the electrode EL to between the vertical structure VS and the insulating layer ILD. The charge storage layer CIL and the blocking insulating layer BLK may extend from between the vertical structure VS and the electrode EL onto the top surface and the bottom surface of the electrode EL. In other words, the charge storage layer CIL and the blocking insulating layer BLK may be disposed between the electrode EL and the insulating layer ILD adjacent to each other. 
     According to an exemplary embodiment of the inventive concept illustrated in  FIG. 15D , the tunnel dielectric layer TIL, the charge storage layer CIL, and the blocking dielectric layer BLK may extend from between the vertical structure VS and the electrode EL onto the top surface and the bottom surface of the electrode EL. In other words, the tunnel dielectric layer TIL, the charge storage layer CIL, and the blocking dielectric layer BLK may be disposed between the electrode EL and the insulating layer ILD adjacent to each other. 
     The charge storage layer CIL of the data storage layer DS may include trap site-rich insulating layers or insulating layers including nano particles. The charge storage layer CIL may be formed using a chemical vapor deposition (CVD) technique or an atomic layer deposition (ALD) technique. For example, the charge storage layer CIL may include a trap insulating layer, a floating gate electrode, or an insulating layer including conductive nano dots. In an exemplary embodiment of the inventive concept, the charge storage layer CIL may include a silicon nitride layer, a silicon oxynitride layer, a silicon-rich nitride layer, a nano-crystalline silicon layer, or a laminated trap layer. 
     The tunnel dielectric layer TIL may include a material having an energy band gap greater than that of the charge storage layer CIL and may be formed by a CVD technique or an ALD technique. For example, the tunnel dielectric layer TIL may include a silicon oxide layer formed by the CVD technique or the ALD technique. In addition, a thermal treatment process may be performed on the tunnel dielectric layer TIL deposited by the CVD or ALD technique. The thermal treatment process may be a rapid thermal nitridation (RTN) process or an annealing process performed in an atmosphere including nitrogen or oxygen. 
     The blocking dielectric layer BLK may include first and second blocking dielectric layers that are formed of different materials from each other. One of the first and second blocking dielectric layers may include a material of which an energy band gap is smaller than that of the tunnel dielectric layer TIL and greater than that of the charge storage layer CIL. Each of the first and second blocking dielectric layers may be formed by a CVD technique or an ALD technique. At least one of the first and second blocking dielectric layers may be formed by a wet oxidation process. In an exemplary embodiment of the inventive concept, the first blocking dielectric layer may include a high-k dielectric layer such as an aluminum oxide layer or a hafnium oxide layer, and the second blocking dielectric layer may include a material of which a dielectric constant is lower than that of the first blocking dielectric layer. In an exemplary embodiment of the inventive concept, the second blocking dielectric layer may include at least one of the aforementioned high-k dielectric layers, and the first blocking dielectric layer may include a material of which a dielectric constant is lower than that of the second blocking dielectric layer. 
       FIGS. 16A and 16B  are enlarged views of a portion ‘B’ of  FIG. 13 , according to an exemplary embodiment of the inventive concept. 
     Referring to  FIGS. 16A and 16B , the vertical structure VS may include a first semiconductor pattern SP 1  connected to the semiconductor layer  70  and a second semiconductor pattern SP 2  disposed between the first semiconductor pattern SP 1  and the data storage layer DS. The first and second semiconductor patterns SP 1  and SP 2  may include a semiconductor material. In an exemplary embodiment of the inventive concept, the first semiconductor pattern SP 1  may have a circular pillar shape. In an exemplary embodiment of the inventive concept, the first semiconductor pattern SP 1  may have a hollow pipe shape or a hollow macaroni shape. In this case, the first semiconductor pattern SP 1  may have a closed bottom end and an inside of the first semiconductor pattern SP 1  may be filled with an insulating material. 
     The data storage layer DS may be disposed between the vertical structure VS and the stack structure ST. The data storage layer DS may include a vertical pattern VP penetrating the stack structure ST and a horizontal pattern HP extending from between the vertical pattern VP and the electrode EL onto the top surface and the bottom surface of the electrode EL. 
     The common source region  71  formed in the semiconductor layer  70  may include dopants having the second conductivity type and may be spaced apart from the top surface of the well plate electrode  60 . According to an exemplary embodiment of the inventive concept illustrated in  FIG. 16B , the semiconductor layer  70  may include a well dopant region  70   w  that has the first conductivity type and is in contact with the well plate electrode  60 . The well dopant region  70   w  may be heavily doped to reduce an ohmic resistance between the well plate electrode  60  and the semiconductor layer  70 . The common source region  71  having the second conductivity type may be spaced apart from the well dopant region  70   w.    
     The well plate electrode  60  may be thinner than the semiconductor layer  70  and may be connected to the well contact plug WCP. In an exemplary embodiment of the inventive concept, the well contact plug WCP may include a barrier metal layer M 1  and a metal layer M 2 . The well plate electrode  60  may be formed of the same material as the barrier metal layer M 1 . For example, the barrier metal layer M 1  may include tantalum (Ta), tantalum nitride (TaN), tantalum-silicon nitride (TaSiN), titanium (Ti), titanium nitride (TiN), titanium-silicon nitride (TiSiN), tungsten (W), or tungsten nitride (WN). The metal layer M 2  may include tungsten (W), aluminum (Al), copper (Cu), or a copper alloy. In other words, in an exemplary embodiment of the inventive concept, the well plate electrode  60  may be formed of the same material as the barrier metal layer M 1  of which an electrical conductivity is lower than that of the metal layer M 2 . Thus, a contact resistance between the well plate electrode  60  and the semiconductor layer  70  may be reduced as well as a reactivity between the well plate electrode  60  and the semiconductor layer  70 . 
       FIGS. 17A, 17B, and 17C  are perspective views each illustrating peripheral logic structures of 3D semiconductor memory devices according to an exemplary embodiment of the inventive concept. 
     A peripheral logic structure PS may include peripheral logic circuits integrated on a semiconductor substrate  10 , a lower interconnection structure electrically connected to the peripheral logic circuits, and a lower insulation layer  50  covering the peripheral logic circuits and the lower interconnection structure. 
     According to an exemplary embodiment of the inventive concept illustrated in  FIG. 17A , the lower interconnection structure may include first lower interconnections  43  electrically connected to the page buffer  20 , a linking interconnection  41  electrically connected to the voltage generator  30 , and second lower interconnections  45 . 
     The first lower interconnections  43  and the second lower interconnections  45  may extend in parallel to each other along one direction and may be disposed at the same level from a top surface of the semiconductor substrate  10 . Positions of the second lower interconnections  45  may be freely changed under the well plate electrode  60 . 
     In an exemplary embodiment of the inventive concept, the first lower interconnections  43  may be arranged between the second lower interconnections  45  spaced apart from each other. The second lower interconnections  45  spaced apart from each other may be connected in common to the linking interconnection  41  through contact plugs, and the linking interconnection  41  may be electrically connected to the voltage generator  30  through a contact plug. The well contact plugs WCP may be connected to top surfaces of the second lower interconnections  45  and may also be connected to the well plate electrode  60  having the plate shape. 
     The number of the second lower interconnections  45  is two in  FIG. 17A . However, the inventive concept is not limited thereto. In an exemplary embodiment of the inventive concept, the number of the second lower interconnections  45  may be greater than two, and the linking interconnection  41  may be provided in plural. 
     According to an exemplary embodiment of the inventive concept illustrated in  FIG. 17B , a lower interconnection structure may include first lower interconnections  43  electrically connected to the page buffer  20  and a second lower interconnection  45  electrically connected to the voltage generator  30 . The first lower interconnections  43  and the second lower interconnection  45  may extend in parallel to each other along one direction and may be disposed at the same level from the top surface of the semiconductor substrate  10 . In the present embodiment, the second lower interconnection  45  may be directly connected to the voltage generator  30  through a contact plug. In other words, the linking interconnection  41  of  FIG. 17A  may be omitted in the present embodiment. A position of the second lower interconnection  45  may be freely changed under the well plate electrode  60 . The well contact plugs WCP may be connected to the top surface of the second lower interconnection  45  and may also be connected to the well plate electrode  60  having the plate shape. In the present embodiment, the well plate electrode  60  may be electrically connected to the voltage generator  30  through one second lower interconnection  45 . 
     According to an exemplary embodiment of the inventive concept illustrated in  FIG. 17C , the well plate electrode  60  may be directly connected to the voltage generator  30  through the well contact plug WCP. In other words, the linking interconnection  41  and the second lower interconnection  45  of  FIG. 17A  may be omitted in the present embodiment. Since the well plate electrode  60  has the plate shape in the present embodiment, positions of the well contact plug WCP and voltage generator  30  may be freely changed under the well plate electrode  60 . 
       FIGS. 18A and 18B  each illustrate a well plate electrode included in a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIGS. 18A and 18B , a well plate electrode  60  may be disposed on the bottom surface of the semiconductor layer  70 , and electrodes EL may be vertically stacked on the top surface of the semiconductor layer  70 . An area of the lowermost electrode EL may be substantially equal to an area of the semiconductor layer  70 . Areas of the electrodes EL may decrease as a distance from the top surface of the semiconductor layer  70  increases. 
     In the embodiments illustrated in  FIGS. 18A and 18B , the well plate electrode  60  may be in contact with a portion of the semiconductor layer  70 . For example, as illustrated in  FIG. 18A , the well plate electrode  60  may have a line shape that intersects a central portion of the semiconductor layer  70 . Additionally, the well plate electrode  60  may have an island shape that overlaps a central portion of the semiconductor layer  70 , as illustrated in  FIG. 18B . 
       FIGS. 19 and 20  are cross-sectional views respectively taken along lines I-I′ and II-II′ of  FIG. 11  to illustrate a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept.  FIG. 21  is an enlarged view of a portion ‘B’ of  FIG. 20 , according to an exemplary embodiment of the inventive concept. 
     Referring to  FIGS. 19 and 20 , a cell array structure CS may be stacked on a peripheral logic structure PS. In other words, the cell array structure CS may overlap the peripheral logic structure PS when viewed from a plan view. 
     As described above, the peripheral logic structure PS may include the peripheral logic circuits such as the row and column decoders ( 2  and  4  of  FIG. 1 ), the page buffer ( 3  of  FIG. 1 ), and the control circuits ( 5  of  FIG. 1 ). The peripheral logic circuits may be integrated on an entire top surface of a semiconductor substrate  10 . In addition, the peripheral logic structure PS may further include a lower interconnection structure electrically connected to the peripheral logic circuits and a lower insulation layer  50  covering the peripheral logic circuits and the lower interconnection structure. 
     According to an exemplary embodiment of the inventive concept, the lower interconnection structure may be disposed between the cell array structure CS and the peripheral logic circuits in a vertical view. The lower interconnection structure may include first lower interconnections  43 , a linking interconnection  41 , and second lower interconnections  45 . The first lower interconnections  43  may be electrically connected to the page buffer  20 . The linking interconnection  41  and the second lower interconnections  45  may be electrically connected to the voltage generator  30 . In addition, one or more well contact plugs WCP may be connected to the second lower interconnections  45 . Top surfaces of the well contact plugs WCP may be substantially coplanar with the top surface of the lower insulation layer  50 . 
     According to an exemplary embodiment of the inventive concept, the cell array structure CS may include a well plate electrode  60 , a semiconductor layer  70  covering the well plate electrode  60 , stack structures ST disposed on the semiconductor layer  70 , and vertical structures VS penetrating each of the stack structures ST. Each of the stack structures ST may include electrodes EL vertically stacked on the semiconductor layer  70 . 
     As described above, the well plate electrode  60  may be disposed on the top surface of the lower insulation layer  50  and may be in contact with the top surfaces of the well contact plugs WCP. In an exemplary embodiment of the inventive concept, the well plate electrode  60  may have a plate shape. The well plate electrode  60  may be electrically connected to the voltage generator  30  through the second lower interconnections  45  and the linking interconnection  41 . 
     The semiconductor layer  70  may be in direct contact with the top surface of the well plate electrode  60 . In an exemplary embodiment of the inventive concept, an area of the semiconductor layer  70  may be substantially equal to an area of the well plate electrode  60 . 
     The stack structures ST may extend in parallel to each other in a first direction D 1  on the semiconductor layer  70  and may be spaced apart from each other in a second direction D 2 . Each of the stack structures ST may include the electrodes EL and insulating layers ILD which are alternately and repeatedly stacked on the semiconductor layer  70 . 
     According to the present embodiment, each of the vertical structures VS may include a lower semiconductor pattern LSP penetrating a lower portion of the stack structure ST and an upper semiconductor pattern USP penetrating an upper portion of the stack structure ST. The lower semiconductor pattern LSP may be connected to the semiconductor layer  70 , and the upper semiconductor pattern USP may be connected to the lower semiconductor pattern LSP. In the present embodiment, the vertical pattern VP of the data storage layer DS may be disposed between the upper semiconductor pattern USP and the stack structure ST, as illustrated in  FIG. 21 . 
     According to an exemplary embodiment of the inventive concept, the upper semiconductor pattern USP may have a hollow pipe shape or a hollow macaroni shape. Here, a bottom end of the upper semiconductor pattern USP may be closed, and an inside of the upper semiconductor pattern USP may be filled with an insulating pattern. In addition, a bottom surface of the upper semiconductor pattern USP may be lower than a topmost portion of a top surface of the lower semiconductor pattern LSP. In other words, a portion of the top surface of the lower semiconductor pattern LSP may be recessed, and a bottom end portion of the upper semiconductor pattern USP may be inserted into the recessed region of the top surface of the lower semiconductor pattern LSP. The upper semiconductor pattern USP may be formed of a semiconductor material. For example, the upper semiconductor pattern USP may include silicon (Si), germanium (Ge), or a mixture thereof. The upper semiconductor pattern USP may be formed of a semiconductor material doped with dopants or an intrinsic semiconductor material not doped with dopants. The upper semiconductor pattern USP may have a single-crystalline structure, an amorphous structure, or a poly-crystalline structure. In addition, the upper semiconductor pattern USP may have a conductive pad corresponding to its top end portion. The conductive pad may be a dopant region doped with dopants or may be formed of a conductive material. 
     In more detail, the upper semiconductor pattern USP may include a first semiconductor pattern SP 1  and a second semiconductor pattern SP 2 , as illustrated in  FIG. 21 . The first semiconductor pattern SP 1  may be connected to the lower semiconductor pattern LSP and may have a pipe or macaroni shape having a closed bottom end. The inside of the first semiconductor pattern SP 1  may be filled with an insulating pattern. The first semiconductor pattern SP 1  may be in contact with an inner sidewall of the second semiconductor pattern SP 2  and the top surface of the lower semiconductor pattern LSP. In other words, the first semiconductor pattern SP 1  may electrically connect the second semiconductor pattern SP 2  to the lower semiconductor pattern LSP. The second semiconductor pattern SP 2  may cover an inner sidewall of the stack structure ST. The second semiconductor pattern SP 2  may have a pipe or macaroni shape of which top and bottom ends are opened. The second semiconductor pattern SP 2  may not be in contact with the lower semiconductor pattern LSP but may be spaced apart from the lower semiconductor pattern LSP. The first and second semiconductor patterns SP 1  and SP 2  may be undoped or may be doped with dopants having the same conductivity type as the semiconductor layer  70 . The first and second semiconductor patterns SP 1  and SP 2  may be in a poly-crystalline state or a single-crystalline state. 
     According to an exemplary embodiment of the inventive concept, the lower semiconductor pattern LSP may be used as a channel region of the ground selection transistor GST described with reference to  FIG. 3 . The lower semiconductor pattern LSP may be formed of a semiconductor material having the same conductivity type as the semiconductor layer  70 . In an exemplary embodiment of the inventive concept, the lower semiconductor pattern LSP may be an epitaxial pattern that is formed by an epitaxial technique or a laser crystallization technique which uses the semiconductor layer  70  as a seed. In this case, the lower semiconductor pattern LSP may have a single-crystalline structure or may have a poly-crystalline structure of which a grain size is greater than that of a semiconductor material formed by a CVD technique. In an exemplary embodiment of the inventive concept, the lower semiconductor pattern LSP may be formed of a poly-crystalline semiconductor material (e.g., poly-crystalline silicon). According to an exemplary embodiment of the inventive concept, the insulating layer ILD adjacent to the lower semiconductor pattern LSP may be in direct contact with a sidewall of the lower semiconductor pattern LSP. 
     In an exemplary embodiment of the inventive concept, the lower semiconductor pattern LSP may have a pillar shape penetrating the lowermost electrode EL, as illustrated in  FIG. 21 . A bottom surface of the lower semiconductor pattern LSP may be lower than the top surface of the semiconductor layer  70  and may be spaced apart from the well plate electrode  60 . The top surface of the lower semiconductor pattern LSP may be higher than a top surface of the lowermost electrode EL. 
       FIG. 22  is a view illustrating an erasing operation of a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. The 3D semiconductor memory device according to the present embodiment may be a NAND flash memory device like that described with reference to  FIG. 3 . 
     Referring to  FIG. 22 , during the erase operation of the NAND flash memory device, a voltage difference may be provided between the vertical structure VS including the semiconductor material and the word line to discharge charges stored in the data storage layer DS to the vertical structure VS. 
     An erase voltage V ERS  generated from the voltage generator  30  may be applied to the well plate electrode  60  during the erase operation. For example, the erase voltage V ERS  may be in a range of 10V to 20V. A ground voltage Vss may be applied to the word lines WL. The ground selection line GSL, the string selection line SSL, the bit line BL, and the common source plug CSPLG may be floated during the erase operation. 
     Under the voltage conditions described above, the erase voltage V ERS  applied to the well plate electrode  60  may be transmitted to the semiconductor layer  70  and the vertical structure VS including the semiconductor material. Thus, a large voltage difference may be provided between the vertical structure VS and the word lines WL to discharge the charges stored in the data storage layer DS to the vertical structure VS by Fowler-Nordheim tunneling. According to an exemplary embodiment of the inventive concept, since the erase voltage V ERS  may be applied to the entire bottom surface of the semiconductor layer  70  through the well plate electrode  60 , a difference between the erase voltage V ERS  transmitted to the vertical structure VS disposed in a central region of the cell array structure CS and the erase voltage V ERS  transmitted to the vertical structure VS disposed in an edge region of the cell array structure CS can be reduced or minimized. 
       FIG. 23  is a block diagram illustrating an electronic system including a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 23 , an electronic system  1100  may be applied to a personal digital assistant (PDA), a portable computer, a web tablet, a wireless phone, a mobile phone, a digital music player, a memory card, or other electronic products for receiving and/or transmitting information data wirelessly. 
     The electronic system  1100  may include a controller  1110 , an input/output (I/O) unit  1120 , a memory device  1130 , an interface unit  1140 , and a data bus  1150 . At least two of the controller  1110 , the I/O unit  1120 , the memory device  1130 , and the interface unit  1140  may communicate with each other through the data bus  1150 . 
     The controller  1110  may include at least one of a microprocessor, a digital signal processor, a microcontroller, or other logic devices having a similar function to any one thereof. The memory device  1130  may store data and/or commands executed by the controller  1110 . The I/O unit  1120  may receive data or signals from the outside or may output data or signals to the outside. For example, the I/O unit  1120  may include a keypad, a keyboard and/or a display device. 
     The memory device  1130  may include a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. In addition, the memory device  1130  may further include another type of memory device or a random access non-volatile memory device. 
     The interface unit  1140  may transmit electrical data to a communication network and/or may receive electrical data from a communication network. 
       FIG. 24  is a block diagram illustrating a memory card including a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 24 , a memory card  1200  used for storing data may include a memory device  1210  implemented with a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. The memory card  1200  may include a memory controller  1220  that controls data communication between a host and the memory device  1210 . 
     A static random access memory (SRAM) device  1221  may be used as a working memory of a central processing unit (CPU)  1222 . A host interface unit  1223  may be configured to include a data communication protocol between the memory card  1200  and the host. An error check and correction (ECC) block  1224  may detect and correct errors of data which are read out from the memory device  1210 . A memory interface unit  1225  may interface with the memory device  1210 . The CPU  1222  may control overall operations for data communication of the memory controller  1220 . The memory card  1200  may further include a read only memory (ROM) device that stores code data used for interfacing with the host. 
       FIG. 25  is a block diagram illustrating an information processing system including a 3D semiconductor memory device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 25 , a memory system  1310  may be installed in an information processing system  1300  such as a mobile device or a desktop computer. The information processing system  1300  may include a modem  1320 , a CPU  1330 , a RAM  1340 , and a user interface unit  1350  that are electrically connected to the memory system  1310  through a system bus  1360 . The memory system  1310  may have the substantially same structure as the memory card  1200  described with reference to  FIG. 24 . In other words, the memory system  1310  may include a memory device  1311  and a memory controller  1312 . The memory system  1310  may store data processed by the CPU  1330  or data inputted from an external system. In an exemplary embodiment of the inventive concept, the memory system  1310  may be a solid state disk (SSD). In this case, the information processing system  1300  may stably store data in the memory system  1310 . In addition, as reliability of the memory system  1310  increases, the memory system  1310  may reduce a resource consumed for correcting errors. Thus, the information processing system  1300  may perform a fast data exchange function. The information processing system  1300  may further include an application chipset, a camera image processor (CIS), and/or an input/output (I/O) unit. 
     The 3D semiconductor memory devices and/or the memory system described above may be encapsulated using various packaging techniques. For example, the 3D semiconductor memory devices and/or the memory system according to the aforementioned exemplary embodiments of the inventive concept may be encapsulated using any one of a package on package (POP) technique, a ball grid arrays (BGAs) technique, a chip scale packages (CSPs) technique, a plastic leaded chip carrier (PLCC) technique, a plastic dual in-line package (PDIP) technique, a die in waffle pack technique, a die in wafer form technique, a chip on board (COB) technique, a ceramic dual in-line package (CERDIP) technique, a plastic metric quad flat package (PMQFP) technique, a plastic quad flat package (PQFP) technique, a small outline package (SOP) technique, a shrink small outline package (SSOP) technique, a thin small outline package (TSOP) technique, a thin quad flat package (TQFP) technique, a system in package (SIP) technique, a multi-chip package (MCP) technique, a wafer-level fabricated package (WFP) technique and a wafer-level processed stack package (WSP) technique. 
     According to an exemplary embodiment of the inventive concept, a cell array structure may be formed on a peripheral logic structure. The cell array structure may include may include a semiconductor layer formed on a top surface of a well plate electrode and memory cells three-dimensionally arranged on the semiconductor layer. During the erase operation of the memory cells, an erase voltage may be applied to the semiconductor layer and the memory cells through the well plate electrode covering a bottom surface of the semiconductor layer. In other words, the erase voltage may be applied to the entire bottom surface of the semiconductor layer, such that the voltage drop may be reduced when the erase voltage is transmitted to the three-dimensionally arranged memory cells. 
     While the inventive concept has been described with reference to exemplary embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications may be made thereto without departing from the scope of the inventive concept as defined by the following claims and their equivalents.