Abstract: A method for semiconductor fabrication. The method includes providing a silicon substrate and forming a tunnel oxide layer over the silicon substrate. Thereafter, a nitride layer is formed over the tunnel oxide layer. The nitride layer and the tunnel oxide layer are etched except where at least one nonvolatile silicon oxide nitride oxide silicon (SONOS) transistor is formed. Additionally, oxide layers are simultaneously formed over the nitride layer corresponding to where at bast one SONOS memory transistor is formed and over the exposed silicon substrate corresponding to where at least one metal oxide semiconductor (MOS) transistor is formed.

Abstract: Methods and apparatuses are disclosed for biasing the source-side and the drain-side of a nonvolatile memory to add electrons to the charge trapping structure.

Abstract: Disclosed are a dual bit type NROM flash memory device and a method for manufacturing the same using a self-aligned scheme. The flash memory device includes a plurality of bit lines buried in a substrate in one direction while being spaced apart from each other at a regular interval; floating gates aligned at both sides of each of the bit lines on the substrate; and a plurality of word lines spaced apart from each other at a regular interval while crossing the bit lines. In the flash memory device of an embodiment, polysilicon is used for a trapping layer, so the programming and erasing operations can be performed at a higher speed, a threshold voltage (Vt) window is widened, and retention characteristics are improved.

Abstract: A method for manufacturing NAND memory cells includes providing a substrate having a first doped region formed therein; forming a first dielectric layer, a storage layer and a patterned hard mask on the substrate; forming a STI in the substrate through the patterned hard mask and removing the patterned hard mask to define a plurality of recesses; forming a second dielectric layer and a first conductive layer filling the recesses on the substrate; and performing a planarization process to remove a portion of the first conductive layer and the second dielectric layer to form a plurality of self-aligned islanding gate structures.

Abstract: A semiconductor device includes a region in a semiconductor substrate having a top surface with a first charge storage layer on the top surface. A first conductive line is on the first charge storage layer. A second charge storage layer is on the top surface. A second conductive line is on the second charge storage layer. A third charge storage layer is on the top surface. A third conductive line is on the third charge storage layer. A fourth charge storage layer has a first side adjoining a first sidewall of the first conductive line and a second side adjoining a first sidewall of the second conductive line. A fifth charge storage layer has a first side adjoining a second sidewall of the second conductive line and a second side adjoining a first sidewall of the third conductive line. Source and drain regions are formed in the substrate on either side of the semiconductor device.

Abstract: A MONOS type non-volatile semiconductor memory device which is capable of electrically writing, erasing, reading and retaining data, the memory device including source/drain regions, a first gate insulating layer, a first charge trapping layer formed on the first gate insulating layer, a second gate insulating layer formed on the first charge trapping layer, and a controlling electrode formed on the second gate insulating layer. The first charge trapping layer includes an insulating film containing Al and O as major elements and having a defect pair formed of a complex of an interstitial O atom and a tetravalent cationic atom substituting for an Al atom, the insulating film also having electron unoccupied levels within the range of 2 eV-6 eV as measured from the valence band maximum of Al2O3.

Abstract: A nonvolatile memory device includes a channel protruding in a vertical direction from a substrate, a plurality of interlayer dielectric layers and gate electrode layers which are alternately stacked over the substrate along the channel, and a memory layer formed between the channel and a stacked structure of the interlayer dielectric layers and gate electrode layers. Two or more gate electrode layers of the plurality of gate electrode layers are coupled to an interconnection line to form a selection transistor.

Abstract: A non-volatile memory device includes a channel structure extended in a first direction that includes a plurality of inter-layer dielectric layers and a plurality of channel layers alternately stacked over a substrate such that each inter-layer dielectric layer is adjacent to a corresponding one of the plurality of channel layers. A word line extends in a second direction crossing the first direction over the channel structure, and a gate electrode protrudes from the word line in a downward direction to contact a sidewall of the channel structure. A memory gate insulation layer is interposed between the gate electrode and the channel structure, where sidewalls of the channel layers contacting the gate electrode are protruded toward the gate electrode, compared with sidewalls of the inter-layer dielectric layers.

Abstract: A nonvolatile memory device includes a string selection transistor, a plurality of memory cell transistors, and a ground selection transistor electrically connected in series to the string selection transistor and to the pluralities of memory cell transistors. First impurity layers are formed at boundaries of the channels and the source/drain regions of the memory cell transistors. The first impurity layers are doped with opposite conductivity type impurities relative to the source/drain regions of the memory cell transistors. Second impurity layers are formed at boundaries between a channel and a drain region of the string selection transistor and between a channel and a source region of the ground selection transistor. The second impurity layers are doped with the same conductivity type impurities as the first impurity layers and have a higher impurity concentration than the first impurity layers.

Abstract: A non-volatile memory device includes a substrate including a resistor layer having a resistance lower than that of a source line, channel structures including a plurality of inter-layer dielectric layers that are alternately staked with a plurality of channel layers over the substrate, and the source line configured to contact sidewalls of the channel layers, where a lower end of the source line contacts the resistor layer.

Abstract: A memory array includes a plurality of bit lines and a plurality of word lines, a gate region, and a charge trapping layer. The charge trapping layer is wider than a word line; the charge trapping layer is extended beyond the edge of the gate region to facilitate capturing and removing charges.

Abstract: A semiconductor non-volatile memory (NVM) device, comprising: a semiconductor substrate; a three-layer stack structure of medium layer-charge trapping layer-medium layer disposed on the semiconductor substrate; a gate disposed above the three-layer stack structure; a source and a drain disposed in the semiconductor substrate at either side of the three-layer stack structure; wherein the charge trapping layer is a dielectric layer containing one or more discrete compound clusters formed by atomic layer deposition (ALD) method.

Abstract: A semiconductor device of an embodiment can prevent nitriding of the lower-layer insulating film and oxygen diffusion from the upper-layer insulating film, so as to minimize the decrease in charge capture density. This semiconductor device includes a semiconductor layer, a first insulating film provided on the semiconductor layer, a nitrogen-added amorphous silicon layer formed on the first insulating film, a first silicon nitride layer formed on the amorphous silicon layer, and a second insulating film formed above the first silicon nitride layer.

Abstract: Provided are an architecture for a non-volatile memory device that can increase the write efficiency for split-gate trap memory, as well as increase resistance to disturbances; and a method of manufacturing said memory device. The device includes, at least: a layered film having traps, formed on top of the semiconductor substrate; a memory gate electrode formed on top of the layered film; a word gate electrode laid out so as to contact the memory gate electrode and the substrate through an insulating film; and source and drain regions in the substrate, sandwiching the two gate electrodes. The equivalent oxide thickness of the insulating film sandwiched between the word gate electrode and the substrate is made greater where the layered film is in contact than where there is no contact.

Abstract: A multiple layer tunnel insulator is fabricated between a substrate and a discrete trap layer. The properties of the multiple layers determines the volatility of the memory device. The composition of each layer and/or the quantity of layers is adjusted to fabricate either a DRAM device, a non-volatile memory device, or both simultaneously.

Abstract: Embodiments of the present technology are directed toward gate sidewall engineering of field effect transistors. The techniques include formation of a blocking dielectric region and nitridation of a surface thereof. After nitridation of the blocking dielectric region, a gate region is formed thereon and the sidewalls of the gate region are oxidized to round off gate sharp corners and reduce the electrical field at the gate corners.

Abstract: A vertical memory device may include a substrate, a first selection line on the substrate, a plurality of word lines on the first selection line, a second selection line on the plurality of word lines, and a semiconductor channel. The first selection line may be between the plurality of word lines and the substrate, and the plurality of word lines may be between the first and second selection lines. Moreover, the first and second selection lines and the plurality of word lines may be spaced apart in a direction perpendicular with respect to a surface of the substrate. The semiconductor channel may extend away from the surface of the substrate adjacent sidewalls of the first and second selection lines and the plurality of word lines. In addition, portions of the semiconductor channel adjacent the second selection line may be doped with indium and/or gallium. Related methods are also discussed.

Abstract: Provided is a nonvolatile memory device having a three dimensional structure. The nonvolatile memory device may include cell arrays having a plurality of conductive patterns having a line shape three dimensionally arranged on a semiconductor substrate, the cell arrays being separated from one another; semiconductor patterns extending from the semiconductor substrate to cross sidewalls of the conductive patterns; common source regions provided in the semiconductor substrate under a lower portion of the semiconductor patterns in a direction in which the conductive patterns extend; a first impurity region provided in the semiconductor substrate so that the first impurity region extends in a direction crossing the conductive patterns to electrically connect the common source regions; and a first contact hole exposing a portion of the first impurity region between the separated cell arrays.

Abstract: A three-dimensional (3-D) non-volatile memory device includes a plurality of word line structures extended in parallel and including a plurality of interlayer dielectric layers and a plurality of word lines that are alternately stacked over a substrate, a plurality of channels protruding from the substrate configured to penetrate the plurality of interlayer dielectric layers and the plurality of word lines, and an air gap formed between the plurality of word line structures.

Abstract: A nonvolatile memory device includes a pipe gate having a pipe channel hole; a plurality of interlayer insulation layers and a plurality of gate electrodes alternately stacked over the pipe gate; a pair of columnar cell channels passing through the interlayer insulation layers and the gate electrodes and coupling a pipe channel formed in the pile channel hole; a first blocking layer and a charge trapping and charge storage layer formed on sidewalk of the columnar cell channels; and a second blocking layer formed between the first blocking layer and the plurality of gate electrodes.

Abstract: A blocking dielectric engineered, charge trapping memory cell includes a charge trapping element that is separated from a gate by a blocking dielectric including a buffer layer in contact with the charge trapping element, such as silicon dioxide which can be made with high-quality, and a second capping layer in contact with said one of the gate and the channel. The capping layer has a dielectric constant that is higher than that of the first layer, and preferably includes a high-? material. The second layer also has a conduction band offset that is relatively high. A bandgap engineered tunneling layer between the channel and the charge trapping element is provided which, in combination with the multilayer blocking dielectric described herein, provides for high-speed erase operations by hole tunneling. In an alternative, a single layer tunneling layer is used.

Abstract: A nonvolatile semiconductor memory device includes: a multilayer body with a plurality of insulating films and electrode films alternately stacked therein; a plurality of select gate electrodes provided on the multilayer body, extending in one direction orthogonal to a stacking direction of the multilayer body, and spaced from each other; semiconductor pillars penetrating through the multilayer body and the select gate electrodes; and a charge storage film provided between one of the electrode films and one of the semiconductor pillars, two neighboring ones of the semiconductor pillars penetrating through a common one of the select gate electrodes and penetrating through mutually different positions in a width direction of the select gate electrodes.

Abstract: A laminated body is formed by alternately laminating a plurality of dielectric films and electrode films on a silicon substrate. Next, a through hole extending in the lamination direction is formed in the laminated body. Next, a selective nitridation process is performed to selectively form a charge layer made of silicon nitride in a region of an inner surface of the through hole corresponding to the electrode film. Next, a high-pressure oxidation process is performed to form a block layer made of silicon oxide between the charge layer and the electrode film. Next, a tunnel layer made of silicon oxide is formed on an inner side surface of the through hole. Thus, a flash memory can be manufactured in which the charge layer is split for each electrode film.

Abstract: A flash memory device comprises a substrate comprising silicon with a silicon dioxide layer thereon. A silicon-oxygen-nitrogen layer is on the silicon dioxide layer, and the silicon-oxygen-nitrogen layer comprises a shaped concentration level profile of oxygen through the thickness of the layer. A blocking dielectric layer is on the silicon-oxygen-nitrogen layer, and a gate electrode is on the blocking dielectric layer. Oxygen ions can be implanted into a silicon nitride layer to form the silicon-oxygen-nitrogen layer.

Abstract: A semiconductor device includes: a first layer; a second layer; a columnar structural unit; and a side portion. The second layer is provided on a major surface of the first layer. The columnar structural unit is conductive and aligned in the first layer and the second layer to pass through the major surface. The side portion is added to a side wall of the columnar structural unit on the second layer side of the major surface.

Abstract: A semiconductor memory device includes a device isolation pattern defining an active region of a substrate, a buried gate electrode extending longitudinally in a given direction across the active region, a first impurity region and a second impurity region disposed along respective sides of the buried gate electrode, a conductive pad disposed on the substrate and electrically connected to the first impurity region, a first contact plug disposed on the substrate and electrically connected to the second impurity doping region, and a second contact plug disposed on the pad.

Abstract: A vertical structure non-volatile memory device includes a channel region that vertically extends on a substrate. A memory cell string vertically extends on the substrate along a first wall of the channel regions, and includes at least one selection transistor and at least one memory cell. An impurity providing layer is disposed on a second wall of the channel region and includes impurities.

Abstract: A nonvolatile semiconductor memory of an aspect of the present invention includes a memory cell including, a charge storage layer on a gate insulating film, a multilayer insulator on the charge storage layer, and a control gate electrode on the multilayer insulator, the gate insulating film including a first tunnel film, a first high-dielectric-constant film on the first tunnel film and offering a greater dielectric constant than the first tunnel film, and a second tunnel film on the first high-dielectric-constant film and having the same configuration as that of the first tunnel film, the multilayer insulator including a first insulating film, a second high-dielectric-constant film on the first insulating film and offering a greater dielectric constant than the first insulating film, and a second insulating film on the second high-dielectric-constant film and having the same configuration as that of the first insulating film.

Abstract: Some embodiments include memory cells that contain a dynamic random access memory (DRAM) element and a nonvolatile memory (NVM) element. The DRAM element contains two types of DRAM nanoparticles that differ in work function. The NVM contains two types of NVM nanoparticles that differ in trapping depth. The NVM nanoparticles may be in vertically displaced charge-trapping planes. The memory cell contains a tunnel dielectric, and one of the charge-trapping planes of the NVM may be further from the tunnel dielectric than the other. The NVM charge-trapping plane that is further from the tunnel dielectric may contain larger NVM nanoparticles than the other NVM charge-trapping plane. The DRAM element may contain a single charge-trapping plane that has both types of DRAM nanoparticles therein. The memory cells may be incorporated into electronic systems.

Abstract: A method of making a monolithic three dimensional NAND string, includes forming a stack of alternating layers of a first material and a second material different from the first material over a substrate, etching the stack to form at least one opening in the stack, forming a discrete charge storage material layer on a sidewall, forming a tunnel dielectric layer, forming a semiconductor channel material, selectively removing the second material layers without removing the first material layers, etching the discrete charge storage material layer to form a plurality of separate discrete charge storage segments, depositing an insulating material between the first material layers, selectively removing the first material layers to expose side wall of the discrete charge storage segments, forming a blocking dielectric, and forming control gates on the blocking dielectric.

Abstract: An object of the present invention is to provide an integrated semiconductor nonvolatile storage device that can be read at high speed and reprogrammed an increased number of times. In the case of conventional nonvolatile semiconductor storage devices having a split-gate structure, there is a tradeoff between the read current and the maximum allowable number of reprogramming operations. To overcome this problem, an integrated semiconductor nonvolatile storage device of the present invention is configured such that memory cells having different memory gate lengths are integrated on the same chip. This allows the device to be read at high speed and reprogrammed an increased number of times.

Abstract: A nonvolatile semiconductor memory device includes a source region and a drain region provided apart from each other in a semiconductor substrate, a first insulating film provided on a channel region between the source region and the drain region, a charge storage layer provided on the first insulating film, a second insulating film provided on the charge storage layer and including a stacked structure of a lanthanum aluminum silicate film and a dielectric film made of silicon oxide or silicon oxynitride, and a control gate electrode provided on the second insulating film.

Abstract: A memory device comprising: a back gate including a first portion of electrically conductive material, a first portion of dielectric material arranged on the back gate, a semiconductor nanobeam arranged on the first portion of dielectric material, a second portion of dielectric material covering the semiconductor nanobeam, a portion of material capable of receiving electrons and holes, and able to perform storage of electrical charges and covering the second portion of dielectric material, a third portion of dielectric material covering the portion of material capable of performing storage of electrical charges, a front gate including a second portion of electrically conductive material covering the third portion of dielectric material.

Abstract: A contact plug 40 electrically connected to an impurity diffusion region between sidewalls of an adjacent pair of memory cells 1 is provided to pass through an interlayer dielectric film 18. A side wall of a contact hole 41 is covered with a sealing film 42 denser than the interlayer dielectric film 18. The contact plug 40 includes a barrier metal film 43 formed to cover a surface of the sealing film 42 and a bottom surface portion of the contact hole 41 and a metal plug 44 embedded in the contact hole 41 in a state surrounded by the barrier metal film 43.

Abstract: According to one embodiment, a plurality of memory cells are provided on a semiconductor substrate. In each memory cell, a control gate electrode is provided on a charge accumulation layer with an inter-electrode insulation film interposed between the control gate electrode and the charge accumulation layer, an air gap is provided between the charge accumulation layers adjacent to each other in a word line direction, and an insulation film disposed below the inter-electrode insulation film is divided into an upper part and a lower part by the air gap.

Abstract: According to one embodiment, a semiconductor memory device includes a substrate, a stacked body, a conductive member, a semiconductor pillar, and a charge storage layer. The stacked body is provided above the substrate. The stacked body includes a plurality of insulating films stacked alternately with a plurality of electrode films. A plurality of terraces are formed in a stairstep configuration along only a first direction in an end portion of the stacked body on the first-direction side. The first direction is parallel to an upper face of the substrate. The plurality of terraces are configured with upper faces of the electrode films respectively. The conductive member is electrically connected to the terrace to connect electrically the electrode film to the substrate by leading out the electrode film in a second direction parallel to the upper face of the substrate and orthogonal to the first direction.

Abstract: A memory device including a substrate, a plurality of conductive layers, a composite dielectric layer and a plurality of gates are provided. Wherein, the conductive layers are disposed on the substrate. The composite dielectric layer is disposed on the substrate and covers the conductive layers. The composite dielectric layer includes a charge trapping layer. The gates are disposed on the composite dielectric layer and across the conductive layers. Wherein, the conductive layers can be used as local bit lines to reduce the resistance values and improve the performance of the memory device.

Abstract: A method of making a monolithic three dimensional NAND string. The method includes forming a stack of alternating layers of a first material and a second material over a substrate. The first material includes a conductive or semiconductor control gate material and the second material includes an insulating material. The method also includes etching the stack to form at least one opening in the stack, selectively etching the first material to form first recesses in the first material and forming a blocking dielectric in the first recesses. The method also includes forming a plurality of discrete charge storage segments separated from each other in the first recesses over the blocking dielectric, forming a tunnel dielectric over a side wall of the discrete charge storage segments exposed in the at least one opening and forming a semiconductor channel in the at least one opening.

Abstract: According to one embodiment, a memory cell includes a charge storage layer. A first air gap is provided between charge storage layers adjacent in a word line direction. A second air gap is provided between charge storage layers adjacent in a bit line direction.

Abstract: A non-volatile memory device includes a plurality of memory cells stacked along a channel protruded from a substrate, a first select transistor connected to one end of the plurality of memory cells, a first interlayer dielectric layer for being coupled between a source line and the first select transistor, and a second interlayer dielectric layer disposed between the first select transistor and the one end of the plurality of memory cells, and configured to include a first recess region.

Abstract: A non-volatile memory and a manufacturing method thereof are provided. The non-volatile memory includes a substrate, a gate structure, a first doped region, a second doped region and a pair of isolation structures. The gate structure is disposed on the substrate. The gate structure includes a charge storage structure, a gate and spacers. The charge storage structure is disposed on the substrate. The gate is disposed on the charge storage structure. The spacers are disposed on the sidewalls of the gate and the charge storage structure. The first doped region and the second doped region are respectively disposed in the substrate at two sides of the charge storage structure and at least located under the spacers. The isolation structures are respectively disposed in the substrate at two sides of the gate structure.

Abstract: A semiconductor device is disclosed. The semiconductor device includes a semiconductor substrate; a gate insulating film formed above the semiconductor substrate; a charge storage layer formed above the gate insulating film; a multilayered interelectrode insulating film formed in a first region above an upper surface portion of the element isolation insulating film, a second region above a sidewall portion of the charge storage layer and a third region above an upper surface portion of the charge storage layer, the interelectrode insulating film including a stack of an upper silicon oxide film, a middle silicon nitride film, and a lower silicon oxide film; a control gate electrode formed above the interelectrode insulating film; wherein the middle silicon nitride film is thinner in the third region than in the second region and the upper silicon oxide film is thicker in the third region than in the second region.

Abstract: A non-volatile memory and a manufacturing method thereof and a method for operating a memory cell are provided. The non-volatile memory includes a substrate, first and second doped regions, a charged-trapping structure, first and second gates and an inter-gate insulation layer. The first and second doped regions are disposed in the substrate and extend along a first direction. The first and second doped regions are arranged alternately. The charged-trapping structure is disposed on the substrate. The first and second gates are disposed on the charged-trapping structure. Each first gate is located above one of the first doped regions. The second gates extend along a second direction and are located above the second doped regions. The inter-gate insulation layer is disposed between the first gates and the second gates. Adjacent first and second doped regions and the first gate, the second gate and the charged-trapping structure therebetween define a memory cell.

Abstract: A dual port static random access memory cell has pull-down transistors, pull-up transistors, and pass transistors. A first active region has a first pull-down transistor coupled to a true data node, a second pull-down transistor coupled to a complementary data node; a first pass transistor coupled to the true data node, and a second pass transistor coupled to the complementary data node. A second active region has the same size and shape as the first active region and has a third pull-down transistor coupled in parallel to the first-pull down transistor, a fourth pull-down transistor coupled in parallel to the second pull-down transistor; a third pass transistor coupled to the true data node, and a fourth pass transistor coupled to the complementary data node. A first pull-up transistor and a second pull-up transistor are located between the first and second active regions.

Abstract: A semiconductor memory device includes a substrate having a step including a first upper surface and a second upper surface higher than the first upper surface, a memory cell array formed on the first upper surface, and a peripheral circuit formed on the second upper surface and configured to supply an electrical signal to the memory cell array. The memory cell array includes a stacked structure having a plurality of first interconnection layers and a plurality of second interconnection layers respectively connected to the first interconnection layers. The first interconnection layers are stacked on the first upper surface, are separated from each other by insulating films, and extend in a first direction. The second interconnection layers extend upward and are separated from each other by insulating films.

Abstract: A semiconductor device includes bit lines (12) that are provided in a semiconductor substrate (10) an ONO film (14) that is provided on the semiconductor substrate; word lines that are provided on the ONO film (14) and extend in a width direction of the bit lines (12); and a dummy layer (44) that extends in the width direction of the bit lines (12) and is provided in a bit-line contact region (40) having contact holes formed to connect the bit lines (12) with wiring layers (34). In accordance with the present invention, the proximity effect at the time of word line formation can be restrained, and the variation in the widths of the word lines can be made smaller, or current leakage between the bit lines and the semiconductor substrate can be restrained.

Abstract: A plurality of vertical channels of semiconductor material are formed to extend in a vertical direction through the plurality of insulation layers and the plurality of conductive patterns, a gate insulating layer between the conductive pattern and the vertical channels that insulates the conductive pattern from the vertical channels. Conductive contact regions of the at least two of the conductive patterns are in a stepped configuration. An etch stop layer is positioned on the conductive contact regions, wherein the etch stop layer has a first portion on a first one of the plurality of conductive patterns and has a second portion on a second one of the plurality of conductive patterns, wherein the first portion is of a thickness that is greater than a thickness of the second portion.

Abstract: A charge trapping non-volatile memory may be made with a charge trapping medium including a pair of dielectric layers sandwiching a metal or semimetal layer. The metal or semimetal layer may exhibit a lower energy level than either of the adjacent sandwiching charge trapping layers, creating a good electron sink and, in some embodiments, resulting in a thinner charge trapping medium.

Abstract: A semiconductor memory device includes: a semiconductor substrate; a plurality of device isolation regions being disposed in an upper-layer portion of the semiconductor substrate, and dividing the upper-layer portion into a plurality of semiconductor portions extending in a first direction; a plurality of charge storage films which are disposed on one of the plurality of the semiconductor portions and spaced apart from one another in the first direction; a block insulating film disposed covering the plurality of charge storage films; and a word electrode disposed on the block insulating film for each of rows of the plurality of charge storage films arranged in a second direction intersecting the first direction, wherein the block insulating film is disposed continuously in the first direction and in the second direction.

Abstract: A non-volatile semiconductor device includes an n type well formed in a semiconductor substrate having a surface, the surface having a plurality of stripe shaped grooves and a plurality of stripe shaped ribs, a plurality of stripe shaped p type diffusion regions formed in upper parts of each of the plurality of ribs, the plurality of stripe shaped p type diffusion regions being parallel to a longitudinal direction of the ribs, a tunneling insulation film formed on the grooves and the ribs, a charge storage layer formed on the tunneling insulating film, a gate insulation film formed on the charge storage layer, and a plurality of stripe shaped conductors formed on the gate insulating film, the plurality of stripe shaped conductors arranged in a direction intersecting the longitudinal direction of the ribs with a predetermined interval wherein an impurity diffusion structure in the ribs are asymmetric.