Abstract: A three-dimensional array especially adapted for memory elements that reversibly change a level of electrical conductance in response to a voltage difference being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. A two-dimensional array of bit lines to which the memory elements of all planes are connected is oriented vertically from the substrate and through the plurality of planes. A double-global-bit-line architecture provides a pair of global bit lines for each bit lines for accessing a row of memory elements in parallel. A first one of each pair allows the local bit lines of the row to be sensed while a second one of each pair allows local bit lines in an adjacent row to be set to a definite voltage so as to eliminate leakage currents between adjacent rows of local bit lines.

Abstract: A three dimensional stacked nonvolatile semiconductor memory according to examples of the present invention includes a memory cell array comprised of first and second blocks disposed side by side and a driver disposed between the first and second blocks. At least two conductive layers having the same structure as that of the at least two conductive layers in the first and second blocks are disposed on the driver, and select gate lines in the first and second blocks are connected to the driver through the at least two conductive layers on the driver.

Abstract: Program disturb is reduced in a non-volatile storage system by programming storage elements on a selected word line WLn in separate groups, according to the state of their WLn?1 neighbor storage element, and applying an optimal pass voltage to WLn?1 for each group. Initially, the states of the storage elements on WLn?1 are read. A program iteration includes multiple program pulses. A first program pulse is applied to WLn while a first pass voltage is applied to WLn?1, a first group of WLn storage elements is selected for programming, and a second group of WLn storage elements is inhibited. Next, a second program pulse is applied to WLn while a second pass voltage is applied to WLn?1, the second first group of WLn storage elements is selected for programming, and the first group of WLn storage elements is inhibited. A group can include one or more data states.

Abstract: A non-volatile memory device includes a substrate and a tunnel insulation layer pattern, such that each portion of the tunnel insulation pattern extends along a first direction and adjacent portions of the tunnel insulation layer pattern may be separated in a second direction that is substantially perpendicular to the first direction. A non-volatile memory device may include a gate structure formed on the tunnel insulation layer pattern. The gate structure may include a floating gate formed on the tunnel insulation layer pattern along the second direction, a first conductive layer pattern formed on the floating gate in the second direction, a dielectric layer pattern formed on the first conductive layer pattern along the second direction, and a control gate formed on the dielectric layer pattern in the second direction.

Abstract: At least one data-line pair has a first data line aligned with a first column of memory cells and a second data line aligned with a second column of memory cells. The first data line is coupled to the second column of memory cells and the second data line is coupled to the first column of memory cells.

Abstract: A nonvolatile semiconductor memory device includes a first stack unit with a first selection transistor and a second selection transistor formed on a semiconductor substrate and a second stack unit with first insulating layers and first conductive layers stacked alternately on the upper surface of the first stack unit. The second stack unit includes a second insulating layer formed in contact with side walls of the first insulating layer and the first conductive layer, a charge storage layer formed in contact with the second insulating layer for storing electrical charges, a third insulating layer formed in contact with the charge storage layer, and a first semiconductor layer formed in contact with the third insulating layer so as to extend in a stacking direction, with one end connected to one diffusion layer of the first selection transistor and the other end connected to a diffusion layer of the second selection transistor.

Abstract: A multiple time programmable (MTP) memory cell, in accordance with an embodiment, includes a floating gate PMOS transistor, a high voltage NMOS transistor, and an n-well capacitor. The floating gate PMOS transistor includes a source that forms a first terminal of the memory cell, a drain and a gate. The high voltage NMOS transistor includes a source connected to ground, an extended drain connected to the drain of the PMOS transistor, and a gate forming a second terminal of the memory cell. The n-well capacitor includes a first terminal connected to the gate of the PMOS transistor, and a second terminal forming a third terminal of the memory cell. The floating gate PMOS transistor can store a logic state. Combinations of voltages can be applied to the first, second and third terminals of the memory cell to program, inhibit program, read and erase the logic state.

Abstract: At least one data-line pair has a first data line aligned with a first column of memory cells and a second data line aligned with a second column of memory cells. The first data line is coupled to the second column of memory cells and the second data line is coupled to the first column of memory cells.

Abstract: A semiconductor storage device includes a first memory cell for storing two kinds of states, a second memory cell for storing two kinds of states, and a sense amplifier for detecting a potential difference between voltages equivalent to readout currents of the first and second memory cells, respectively. Either one of information data “0” or data “1”, which is stored in combination of the first and second memory cells, is read out by detecting the potential difference equivalent to the readout current difference between the first and second memory cells.

Abstract: A flash memory array comprises a plurality of memory cells organized in a matrix of rows and columns. Each of the memory cells includes a floating gate memory transistor having a source region and a drain region, and a coupling capacitor electrically connected to the memory transistor. A plurality of word lines are each electrically connected to the capacitor in each of the memory cells in a respective row. A first set of bit lines are each electrically connected to the drain region of the memory transistor in each of the memory cells in a respective column. A plurality of high voltage access transistors are each electrically connected to a bit line in the first set of bit lines. A second set of bit lines are each electrically connected to the source region of the memory transistor in each of the memory cells in a respective column.

Abstract: A non-volatile memory device and a method of fabricating the same are disclosed. The method includes the steps of: providing a semiconductor substrate having isolation layers in an isolation region, a tunnel insulating layer formed between the isolation layers, and first electron charge layers formed between the isolation layers, wherein the isolation layers comprise projections extending higher than the semiconductor substrate; etching the first electron charge layers, thereby reducing the thickness of the first electron charge layers and exposing sidewalls of the isolation layers; performing a first etch process to reduce the width of the projections; forming second electron charge layers between the projections on the first electron charge layers; and performing a second etch process to remove the projections between the second electron charge layers.

Abstract: A non-volatile semiconductor storage device includes: a memory cell array having memory cells arranged therein, the memory cells storing data in a non-volatile manner; and a plurality of transfer transistors transferring a voltage to the memory cells, the voltage to be supplied for data read, write and erase operations with respect to the memory cells. Each of the transfer transistors includes: a gate electrode formed on a semiconductor substrate via a gate insulation film; and diffusion layers formed to sandwich the gate electrode therebetween and functioning as drain/source layers. Upper layer wirings are provided above the diffusion layers and provided with a predetermined voltage to prevent depletion of the diffusion layers at least when the transfer transistors become conductive.

Abstract: Silicon-oxide-nitride-oxide-silicon SONOS-type devices (or BE-SONOS) fabricated in Silicon-On-Insulator (SOI) technology for nonvolatile implementations. An ultra-thin tunnel oxide can be implemented providing for very fast program/erase operations, supported by refresh operations as used in classical DRAM technology. The memory arrays are arranged in divided bit line architectures. A gate injection, DRAM cell is described with no tunnel oxide.

Abstract: A flash memory cell includes a p-channel flash transistor having a source, a drain, a floating gate, and a control gate, an n-channel flash transistor having a source, a drain coupled to the drain of the p-channel flash transistor, a floating gate, and a control gate, a switch transistor having a gate coupled to the drains of the p-channel flash transistor and the n-channel flash transistor, a source, and a drain, and an n-channel assist transistor having a drain coupled to the drains of the p-channel flash transistor and the n-channel flash transistor, a source coupled to a fixed potential, and a gate.

Abstract: A memory cell that includes a control gate disposed laterally between two floating gates where each floating gate is capable of holding data. Each floating gate in a memory cell may be erased and programmed by applying a combination of voltages to diffusion regions, the control gate, and a well. A plurality of memory cells creates a memory string, and a memory array is formed from a plurality of memory strings arranged in rows and columns.

Abstract: A non-volatile memory array for an FPGA comprises a plurality of memory cells arranged in rows and columns and divided into a plurality of row segments. The source of each non-volatile memory transistor in each segment is coupled together to a common source line. A column segment line is associated with each segment of the array, and is coupled to the drains of each non-volatile memory transistor in the segment. A segment select transistor is coupled between each column segment line and its associated column line, and a high-voltage driver transistor is coupled to each column line.

Abstract: A flash memory array comprises a plurality of memory cells organized in a matrix of rows and columns. Each of the memory cells includes a floating gate memory transistor having a source region and a drain region, and a coupling capacitor electrically connected to the memory transistor. A plurality of word lines are each electrically connected to the capacitor in each of the memory cells in a respective row. A first set of bit lines are each electrically connected to the drain region of the memory transistor in each of the memory cells in a respective column. A plurality of high voltage access transistors are each electrically connected to a bit line in the first set of bit lines. A second set of bit lines are each electrically connected to the source region of the memory transistor in each of the memory cells in a respective column.

Abstract: An embodiment of a flash memory device comprises a cell array including memory cells coupled to bit lines, a decoder configured to decode successive logical column addresses into physical column addresses that are arranged non-sequentially, and a gate circuit to partially select the bit lines in response to the decoded addresses. Physically adjacent bit lines may be activated so that electrical coupling effects are eliminated by non-successively activating the bit lines.

Abstract: A non-volatile memory device and a method of fabricating the same are disclosed. The method includes the steps of: providing a semiconductor substrate having isolation layers in an isolation region, a tunnel insulating layer formed between the isolation layers, and first electron charge layers formed between the isolation layers, wherein the isolation layers comprise projections extending higher than the semiconductor substrate; etching the first electron charge layers, thereby reducing the thickness of the first electron charge layers and exposing sidewalls of the isolation layers; performing a first etch process to reduce the width of the projections; forming second electron charge layers between the projections on the first electron charge layers; and performing a second etch process to remove the projections between the second electron charge layers.

Abstract: A select gate structure for a non-volatile storage system include a select gate and a coupling electrode which are independently drivable. The coupling electrode is adjacent to a word line in a NAND string and has a voltage applied which reduces gate induced drain lowering (GIDL) program disturb of an adjacent unselected non-volatile storage element. In particular, an elevated voltage can be applied to the coupling electrode when the adjacent word line is used for programming. A reduced voltage is applied when a non-adjacent word line is used for programming. The voltage can also be set based on other programming criterion. The select gate is provided by a first conductive region while the coupling electrode is provided by a second conductive region formed over, and isolated from, the first conductive region.

Abstract: An anti-reflective coating (ARC) is formed over the various layers involved in a cell fabrication process. The ARC is selectively etched such that the edges of the etched areas of the ARC slope downward at an angle determined by the thickness of the ARC. The etching process could include CF4 chemistry. The inner edges of the sloped ARC areas reduce the original photo-defined space since the underlying layers are now defined by the sloped edges.

Abstract: An exemplary NAND string memory array includes at least one plane of memory cells, said memory cells comprising thin film modifiable conductance switch devices and which cells are arranged in a plurality of series-connected NAND strings, said NAND strings including a series select device at each end thereof. Another exemplary NAND string memory array includes a group of more than four adjacent NAND strings within the same memory block each associated with a respective global bit line not shared by the other NAND string of the group. Another exemplary NAND string memory array includes NAND strings on identical pitch as their respective global bit lines.

Abstract: An integrated DRAM-NVRAM, multi-level memory cell is comprised of a vertical DRAM device with a shared vertical gate floating plate device. The floating plate device provides enhanced charge storage for the DRAM part of the cell through the shared floating body in a pillar between the two functions. The memory cell is formed in a substrate with trenches that form pillars. A vertical wordline/gate on one side of a pillar is used to control the DRAM part of the cell. A vertical trapping layer on the other side of the pillar stores one or more charges as part of the floating plate device and to enhance the DRAM function through the floating body between the DRAM and floating plate device. A vertical NVRAM wordline/control gate is formed alongside the trapping layer and is shared with an adjacent floating plate device.

Abstract: A true bit line can extend across a memory cell area of the memory device in a first direction and a complementary bit line can extend across the memory cell area in a second direction opposing the first direction, wherein the true bit line and the complementary bit line comprising a bit line pair.

Abstract: A semiconductor integrated circuit device includes even-numbered bit lines, odd-numbered bit lines, cell source lines, first memory elements electrically connected between the even-numbered bit lines and the cell source lines, and second memory elements electrically connected between the odd-numbered bit lines and the cell source lines and belonging to the same rows as the first memory elements. A potential corresponding to data to be programmed is applied to the first memory element via the even-numbered bit line and a potential which suppresses programming is applied to the second memory element via the cell source line while the odd-numbered bit lines are kept in an electrically floating state when data is programmed into the first memory element.

Abstract: A dynamic programming method for a non-volatile storage device is described. Memory cells are provided arrayed in R rows. Sub bit lines are provided coupled to voltage supply lines through select circuits. During program operation, the select circuits are switched such that one or more of the source side sub bit line or the drain side sub bit line is floating when all other program voltages are applied to a selected cell.

Abstract: An integrated circuit chip includes a number of memory bitcells. Each bitcell includes: a latch having a sense node; a programming transistor having an efficient saturation region of operation; and a fuse connected to the programming transistor at a first terminal of the fuse. A programming voltage can be supplied to the fuse at a second terminal of the fuse; and a logic gate circuit is connected to the gate of the programming transistor. The logic gate circuit is operated at the programming voltage so that the logic gate circuit drives the programming transistor in the efficient saturation region when programming the fuse. The bitcell also includes a fuse-sensing circuit having no more than one transistor. Operation in the efficient saturation region allows the programming transistor to be small. Combined with using no more than one sensing transistor, significant reduction in area of the bitcells on the chip is achieved.

Abstract: Each nonvolatile memory cell transistor has such directivities that a current flows only from the drain to the source and that charge is exchangeable only at the source. The source of one of a pair of memory cell transistors connected to each word line is connected to the drain of the other memory cell transistor, and the drain of the one memory cell transistor is connected to the source of the other. During a data rewrite operation, reverse voltages are applied to the sources and drains of the pair of memory cell transistors. Because of the directivities of each memory cell transistor, charge is exchanged with a charge accumulation layer only in the source region. This makes the data rewritable in only one of the pair of memory cell transistors. As a result, data is rewritable on a memory cell basis without increasing the memory cell size.

Abstract: A characteristic evaluating method of precisely obtaining a resistance value of an offset region in a semiconductor memory element constructed so that the resistance value of the offset region positioned below a memory function element formed on one side or both sides of a gate electrode changes according to an amount of charges or a polarization state of charges accumulated in said memory function element includes: a step of obtaining each of a resistance value between two diffusion regions inclusive formed on both sides of a channel region disposed just below the gate electrode of the semiconductor memory element via a gate insulating film, a resistance value of the channel region, and a resistance value of the diffusion regions; and a step of calculating the resistance value of the offset region which isolates the channel region and the diffusion region from each other on the basis of a result of subtracting the resistance value of the channel region and the resistance value of the diffusion regions from t

Abstract: A flash memory device is disclosed that includes a number of columns each of which is connected with a plurality of memory cells. A column selector circuit selects a part of the columns in response to a column address, and a plurality of sense amplifier groups are connected with the selected columns by the column selector circuit. The column selector circuit variably selects the columns according to whether the column address is 4N-aligned (where N is an integer having a value of 1 or more). For example, the column selector circuit chooses columns of the column address when the column address is 4N-aligned, and chooses columns of an upper column address when the column address is not 4N-aligned.

Abstract: A semiconductor device includes a non-volatile memory, such as an electrically erasable programmable read only memory (EEPROM) array of memory cells. The memory is arranged as an array of cells in rows and columns. Each column of the array is located within an isolated well, common to the cells in the column but isolated from other wells of other columns. The array is programmed by pulsing potentials to each column, with isolation of results for each column. In one embodiment, the memory cells are devoid of floating gate devices and use a non-conductive charge storage layer to store charges. In another embodiment, the memory cells store charges in nanocrystals.

Abstract: A nonvolatile semiconductor memory device of the present invention includes: a plurality of memory blocks each including a memory array including a plurality of memory cells, a plurality of word lines and bit lines provided so as to cross each other for selecting the memory cell, a row decoder for selecting the word line according to an externally-input row address signal, a column decoder for selecting the bit line according to an externally-input column address signal; and at least one internal voltage generation circuit for applying a voltage required for performing data write/erase operations on the memory array, a plurality of first switch circuits are provided such that each first switch circuit is provided between the at least one internal voltage generation circuit and the row decoder or the column decoder, and a switch selection circuit is provided for selectively operating the plurality of first switch circuits.

Abstract: The present invention discloses a non-volatile semiconductor memory device and a method of operating the same. More specifically, the present invention includes a semiconductor substrate having active and field regions, at least two non-volatile storage transistors each of which having a storage on the active region and a control gate at the storage, wherein at least two control gates are incorporated into a single control plate, and at least two selection transistors each of which corresponds to the non-volatile storage transistor, wherein each of the selection transistors connected to the corresponding non-volatile storage transistors for selecting the corresponding non-volatile storage transistors.

Abstract: A nonvolatile semiconductor storage device includes a memory cell array region in which a plurality of memory cells are arranged, each of the memory cells having first and second nonvolatile memory elements and being controlled by one word gate and first and second control gates. In reading out data from one of the first and second nonvolatile memory elements of the memory cell, a control voltage of a control-gate-line selection switching element connected to a sub control gate line to which an override voltage is applied, is greater than that of a control-gate-line selection switching element connected to a sub control gate line to which a read voltage is applied.

Abstract: In a semiconductor integrated circuit device including a third gate, the present invention improves miniaturization and operation speed and reduces a defect density of an insulator film. In a semiconductor integrated circuit device including a well of a first conductivity type formed in a semiconductor substrate, a source/drain diffusion layer of a second conductivity type inside the well, a floating gate formed over the semiconductor substrate through an insulator film, a control gate formed and isolated from the floating gate through an insulator film, word lines formed by connecting the control gates and a third gate formed and isolated from the semiconductor substrate, the floating gate and the control gate through an insulator film and different from the floating gate and the control gate, the third gate is buried into a space of the floating gates existing in a direction vertical to the word line and a channel.

Abstract: A system of Flash EEprom memory chips with controlling circuits serves as non-volatile memory such as that provided by magnetic disk drives. Improvements include selective multiple sector erase, in which any combinations of Flash sectors may be erased together. Selective sectors among the selected combination may also be de-selected during the erase operation. Another improvement is the ability to remap and replace defective cells with substitute cells. The remapping is performed automatically as soon as a defective cell is detected. When the number of defects in a Flash sector becomes large, the whole sector is remapped. Yet another improvement is the use of a write cache to reduce the number of writes to the Flash EEprom memory, thereby minimizing the stress to the device from undergoing too many write/erase cycling.

Abstract: A memory array includes a plurality of sets of transistors, each set including a pair of transistors in series. Each such pair of transistors is connected between a pair of adjacent bit lines. Each of the pair of transistors in each set is associated with a different one of an adjacent pair of word lines. The array is configured by providing substantially strait elongated source/drain regions in side-by-side, parallel relation. Each bit line has a zigzag configuration and connects to a pair of adjacent source/drain regions in alternating manner along the bit line length.

Abstract: An EEPROM segment bit line page memory array includes a plurality of bit lines extending in a Y-direction; a plurality of word lines extending in an X-direction; a plurality of sub-bit lines extending in the Y-direction; a plurality of segment select word lines extending in the X-direction; a plurality of segment select devices arranged in a segment select row; and a plurality of EEPROM floating gate memory devices arranged in the X- and Y-directions. Each of the segment select devices connects one of the sub-bit lines to a corresponding one of the bit-lines. Plural gates of the segment select devices in each segment select row are connected to one of the segment select word lines. Each of the memory devices connects adjacent sub-bit lines, and corresponding control gates of plural memory devices in a memory device row arc electrically connected to one of the word lines.

Abstract: A read-only nonvolatile memory in which the leakage current of unselected memory cell transistors is suppressed. Adjacent memory cell transistors are commonly connected to drain lines, and adjacent memory cell transistors on the other side are commonly connected to source lines. Gates within a same row are commonly connected to a word line. An offset structure is formed on the drain side of each memory cell transistor, and a non-offset structure is formed on the source side. Accordingly, in each memory cell transistor a depletion layer is generated between the drain region and channel region when a drain line is activated, but the depletion layer directly under a drain region does not reach the channel region when the drain line is in a state of high impedance. Therefore, there is no leakage current from the drain to the source in unselected memory cell transistors. Since there is no leakage current flowing from unselected memory cell transistors to source lines, the read margin is enhanced.

Abstract: P channel EEPROM cells are designed for integration into arrays written with single polarity signals developed from small, low power charge pumps. These cells reduce the additional masking steps that must be added to a CMOS logic process for EEPROM to only one additional step. The novel cells of this invention enable the array to function with a VPP about 2 V less than that required by an N channel EEPROM cell, with similar writing speed and tunnel oxide thickness.

Abstract: A plurality of basic unit blocks include a memory cell array and first data lines transmitting data read out from memory cell arrays. Second data lines are arranged in an upper layer in a plurality of basic unit blocks. First power supply wirings are arranged along the second data lines. Second power supply wirings are arranged in a direction orthogonal to the first power supply wirings in the upper layer of the basic unit block of the plurality of basic unit blocks which is positioned on one end. The second power supply wirings are arranged in the same layer where the first power supply wirings are formed, and are connected to the first wirings.

Abstract: An apparatus for storing data of a device, in particular of a motor vehicle, which is to be monitored, in which apparatus the data are preferably stored by means of a control unit in a memory unit. In an apparatus which permits a plurality of data which change continuously during the service life of the motor vehicle to be stored in an operationally reliable way and with a high processing speed, the fixed data and the continuously updated data of the apparatus which is to be monitored are stored in the memory unit 15 which contains the open-loop and/or closed-loop control processes.

Abstract: P channel EEPROM cells are designed for integration into arrays written with single polarity signals developed from small, low power charge pumps. These cells reduce the additional masking steps that must be added to a CMOS logic process for EEPROM to only one additional step. The novel cells of this invention enable the array to function with a VPP about 2 V less than that required by an N channel EEPROM cell, with similar writing speed and tunnel oxide thickness.

Abstract: A method for sensing the state of a memory cell includes both dynamic and static clamping of the bit line coupled to a memory cell. This dual clamping configuration/operation ensures a quick charge of the bit line while eliminating overcharging of the bit line. Thus, sensing the state of the memory cell is substantially independent of the size of the memory array. A sensing system for sensing the state of a memory cell can include a system bit line coupled to a terminal of the memory cell, a charge initiation device for activating a charge operation on the system bit line, and a control unit connected between the system bit line and the charge initiation device. The control unit includes a static clamp to charge the system bit line to a first predetermined voltage and a dynamic clamp to charge the system bit line to a second predetermined voltage.

Abstract: In a semiconductor integrated circuit device including a third gate, the present invention improves miniaturization and operation speed and reduces a defect density of an insulator film. In a semiconductor integrated circuit device including a well of a first conductivity type formed in a semiconductor substrate, a source/drain diffusion layer of a second conductivity type inside the well, a floating gate formed over the semiconductor substrate through an insulator film, a control gate formed and isolated from the floating gate through an insulator film, word lines formed by connecting the control gates and a third gate formed and isolated from the semiconductor substrate, the floating gate and the control gate through an insulator film and different from the floating gate and the control gate, the third gate is buried into a space of the floating gates existing in a direction vertical to the word line and a channel.

Abstract: Instead of using a common substrate (101) for each sector of a flash memory, trenches are used to isolate columnar active substrate regions (304) of the substrate (101), and independent access to each of these columnar regions (304) is provided. First, the independent access to each of these columnar regions (304) provides a capability for achieving more precise control over the voltage on the floating gates (106). For example, flash memory in accordance with the present invention is better suited for multi-level storage (storing of more than 1 bit of information per cell). Second, the independent access to each of these columnar regions (304) also provides a capability for areas of flash memory smaller than an entire sector to be erased at one time. Finally, since both programming and erasing is achieved by way of cold electron tunneling from the columnar active substrate region (304), no high voltages need to be applied to either the drain (102) or source (104).

Abstract: P channel EEPROM cells are designed for integration into arrays written with single polarity signals developed from small, low power charge pumps. These cells reduce the additional masking steps that must be added to a CMOS logic process for EEPROM to only one additional step. The novel cells of this invention enable the array to function with a VPP about 2 V less than that required by an N channel EEPROM cell, with similar writing speed and tunnel oxide thickness.

Abstract: Instead of using a common substrate (101) for each sector of a flash memory, trenches are used to isolate columnar active substrate regions (304) of the substrate (101), and independent access to each of these columnar regions (304) is provided. First, the independent access to each of these columnar regions (304) provides a capability for achieving more precise control over the voltage on the floating gates (106). For example, flash memory in accordance with the present invention is better suited for multi-level storage (storing of more than 1 bit of information per cell). Second, the independent access to each of these columnar regions (304) also provides a capability for areas of flash memory smaller than an entire sector to be erased at one time. Finally, since both programming and erasing is achieved by way of cold electron tunneling from the columnar active substrate region (304), no high voltages need to be applied to either the drain (102) or source (104).

Abstract: On a semiconductor substrate of a first conductive type is formed a well layer of the same conductive type as that of the substrate in electrically separated that is, physically separated and electrically isolated, from the substrate, and a MOS transistor, used as a nonvolatile memory cell, forming a drain region and a source region respectively within the well layer is used as a memory cell. Well layers associated with different columns are connected to each other by a well wiring commonly so that operation voltage different from that of the semiconductor substrate is applied thereto. In the case of data erasing, prescribed positive voltage is applied to a well wiring, and prescribed voltage lower than said positive voltage is applied to a selected word line. In the case of data programming, prescribed negative voltage is applied to the well wiring, prescribed voltage higher than said negative voltage is applied to the selected word line.