Abstract: A flash memory device has a resistivity measurement pattern and method of forming the same. A trench is formed in an isolation film in a Self-Aligned Floating Gate (SAFG) scheme. The trench is buried to form a resistivity measurement floating gate. This allows the resistivity of the floating gate to be measured even in the SAFG scheme. Contacts for resistivity measurement are directly connected to the resistivity measurement floating gate. Therefore, variation in resistivity measurement values, which is incurred by the parasitic interface, can be reduced.

Abstract: A semiconductor device includes a substrate and a first gate oxide layer overlying a first device region and a second device region in the substrate, a first gate in the first device region, and a second gate and a third gate in the second device region. The device also has a first dielectric layer with a first portion disposed on the first gate, a second portion disposed adjacent a sidewall of the first gate, and a third portion disposed over the third gate. An inter-gate oxide layer is disposed on the first gate and between the first portion and the second portion of the first dielectric layer. A fourth gate overlies the second gate oxide layer, the inter-gate oxide layer, and the first portion and the second portion of the first dielectric layer in the first device region. A fifth gate overlies the third portion of the first dielectric layer which is disposed over the third gate in the second device region.

Abstract: A nonvolatile semiconductor memory device includes a semiconductor substrate of a first conductivity type, a pair of source and drain diffusion regions of a second conductivity type oppositely formed on a surface of the semiconductor substrate, and a stacked structure having a gate insulating film, a charge accumulation film, an interlayer insulating film and a control gate which are formed in order on a channel region of the surface of the semiconductor substrate interposed between the source and drain diffusion regions. An edge of the stacked structure in the vicinity of the source region is formed away from a junction position between the source diffusion region and the channel region.

Abstract: A nonvolatile semiconductor memory device includes an array of nonvolatile memory cell transistors, each of which is configured such that a tunnel insulation film, a floating gate electrode, a floating gate insulation film and a control gate electrode are stacked on a surface of a semiconductor substrate. A mean roughness of an interface between a polysilicon, of which the floating gate electrode is formed, and the floating gate insulation film is 1.5 nm or less.

Abstract: A negative differential resistance (NDR) diode and a memory cell incorporating that NDR diode are provided. The NDR diode comprises a p-type germanium region in contact with an n-type germanium region and forming a germanium pn junction diode. A first gate electrode overlies the p-type germanium region, is electrically coupled to the n-type germanium region, and is configured for coupling to a first electrical potential. A second gate electrode overlies the n-type germanium region and is configured for coupling to a second electrical potential. A third electrode is electrically coupled to the p-type germanium region and may be coupled to the second gate electrode. A small SRAM cell uses two such NDR diodes with a single pass transistor.

Abstract: A flash memory device and method of forming a flash memory device are provided. The flash memory device includes a silicon nitride layer having a compositional gradient in which the ratio of silicon to nitrogen varies through the thickness of the layer. The silicon nitride layer having a compositional gradient of silicon and nitrogen provides an increase in charge holding capacity and charge retention time of the unit cell of a non-volatile memory device.

Abstract: A semiconductor device includes a gate electrode having a straight portion, a dummy electrode located at a point on the extension of the straight portion, a stopper insulating film, a sidewall insulating film, an interlayer insulating film, and a linear contact portion extending, when viewed from above, parallel to the straight portion. The longer side of the rectangle defined by the linear contact portion is, when viewed from above, located beyond the sidewall insulating film and within the top region of the gate electrode and the dummy electrode. A gap G between the gate electrode and the dummy electrode appearing, when viewed from above, in the linear contact portion is filled with the sidewall insulating film such that the semiconductor substrate is not exposed.

Abstract: A single-poly EEPROM memory device comprises a control gate isolated within a well of a first conductivity type in a semiconductor body of a second conductivity type, first and second tunneling regions isolated from one another within respective wells of the first conductivity type in the semiconductor body, a read transistor isolated within a well of the first conductivity type, and a floating gate overlying a portion of the control gate, the read transistor, and the first and second tunneling regions. The memory device is configured to be electrically programmed by changing a charge on the floating gate that changes the device threshold voltage. In one embodiment, the memory device is configured to be electrically programmed by applying a first potential between the first and second tunneling regions, and a second potential to the control gate, the second potential having a value less than the first potential.

Abstract: A structure of a non-volatile memory is described, including a substrate, isolation structures disposed in and protrudent over the substrate, floating gates as conductive spacers on the sidewalls of the isolation structures protrudent over the substrate, and a tunneling layer between each floating gate and the substrate. A process for fabricating a non-volatile memory is also described. Isolation structures are formed in a substrate protrudent over the same, a tunneling layer is formed over the substrate, and then floating gates are formed as conductive spacers on the sidewalls of the first isolation structures protrudent over the substrate.

Abstract: A semiconductor memory has a gate electrode and a pair of multilayer memory elements formed on side surfaces of the gate electrode. Each multilayer memory element includes, in sequence from the gate electrode outward, a first silicon oxide layer, a charge trapping silicon nitride layer, a second silicon oxide layer, all with L-shaped cross sections, and a protective silicon nitride layer with an approximately rectangular cross section seated in the L-shape of the second silicon oxide layer. The protective silicon nitride layer protects the charge trapping silicon nitride layer from etching damage during the formation of contact holes without adding to the area occupied by the memory cell.

Abstract: A nonvolatile memory device includes a control gate formed along a first direction over a substrate, an active region formed over the substrate, the active region being defined along a second direction crossing the control gate and including a fin type protruding portion having rounded top corners at a region where the control gate and the active region overlap, a floating gate formed over a surface of the protruding portion of the active region below the control gate and formed to a substantially uniform thickness along the surface profile of the protruding portion of the active region, a tunneling insulation layer formed between the floating gate and the active region, and a dielectric layer formed between the floating gate and the control gate.

Abstract: A semiconductor device includes a substrate, a memory cell formed on the substrate, and a contact to the substrate. The contact is formed in an area away from the memory cell and functions to raise the potential of the substrate.

Abstract: NAND arrays of memory cells are described, as well as methods of forming and using them. Memory cell charge storage devices, such as conductive floating gates, are oriented vertically in trenches, with control gates positioned both in the trenches between charge storage elements and over a horizontal surface between the trenches. Individual charge storage devices are therefore field coupled with two control gates, one on either side.

Abstract: A nonvolatile memory device includes a semiconductor substrate, a tunneling insulation layer on the semiconductor substrate, a charge storage layer on the tunneling insulation layer, an inter-electrode insulation layer on the charge storage layer, and a control gate electrode on the inter-electrode insulation layer. The inter-electrode insulation layer includes a high-k dielectric layer having a dielectric constant greater than that of a silicon nitride, and an interfacial layer between the charge storage layer and the high-k dielectric layer. The interfacial layer includes a silicon oxynitride layer.

Abstract: A example embodiment may provide a memory device that may include an active pattern on a semiconductor substrate, a first charge trapping layer pattern on the active pattern, a first gate electrode on the first charge trapping layer pattern, a second charge trapping layer pattern on a sidewall of the active pattern in a first direction, a second gate electrode on the second charge trapping layer pattern in the first direction, and/or a source/drain region in the active pattern. The memory device may have improved integration by forming a plurality of charge trapping layer patterns on the same active pattern.

Abstract: A flash memory comprising a substrate, a stacked structure over the substrate, a source, a drain and a source-side spacer is provided. The stacked structure includes a tunneling oxide layer, a floating gate on the tunneling oxide layer, an inter-gate dielectric layer on the floating gate and a control gate on the inter-gate dielectric layer. The source and the drain are disposed in the substrate on the sides of the floating gate, respectively. The source-side spacer is disposed on a sidewall of the stacked structure near the source, thereby preventing the tunneling oxide layer and the inter-gate dielectric layer near the source from being re-oxidized, resulting in an increased thickness.

Abstract: A non-volatile memory device includes a floating gate formed on a substrate with a gate insulation layer interposed therebetween, a tunnel insulation layer formed on the floating gate, a select gate electrode inducing charge introduction through the gate insulation layer, and a control gate electrode inducing charge tunneling occurring through the tunnel insulation layer. The select gate electrode is insulated from the control gate electrode. According to the non-volatile memory device, a select gate electrode and a control gate electrode are formed on a floating gate, and thus a voltage is applied to the respective gate electrodes to write and erase data.

Abstract: In a nonvolatile semiconductor memory device provided with memory cell transistors, each of the memory cell transistors has a tunnel insulating film, a floating gate electrode, an inter-electrode insulating film, and element isolation insulating films respectively. The floating gate electrode on the tunnel insulating film is provided with a first floating gate electrode and a second floating gate electrode formed sequentially from the bottom, the second floating gate electrode being narrower in a channel-width direction than the first one. Levels of upper surfaces of the element isolation insulating films and the first floating gate electrode are the same. The inter-electrode insulating film continuously covers the upper and side surfaces of the floating gate electrode and the upper surfaces of the element isolation insulating films, and is higher in a nitrogen concentration in a boundary portion to the floating gate electrode than in boundary portions to the element isolation insulating films.

Abstract: A semiconductor device includes a substrate (12), a first insulating layer (14) over a surface of the substrate (12), a layer of nanocrystals (13) over a surface of the first insulating layer (14), a second insulating layer (15) over the layer of nanocrystals (13). A nitriding ambient is applied to the second insulating layer (15) to form a barrier to further oxidation when a third insulating layer (22) is formed over the substrate (12). The nitridation of the second insulating layer (15) prevents oxidation or shrinkage of the nanocrystals and an increase in the thickness of the first insulating layer 14 without adding complexity to the process flow for manufacturing the semiconductor device (10).

Abstract: A nonvolatile memory device and method for fabricating the same are provided. The method for fabricating the nonvolatile memory device comprises providing a substrate. A tunnel insulating layer and a first conductive layer are formed in the substrate. A trench is formed through the first conductive layer and the tunnel insulating layer, wherein a portion of the substrate is exposed from the trench. A first insulating layer is formed in the trench. A second insulating layer is formed on sidewalls of the first insulating layer. A third insulating layer is conformably formed in the trench, covering the first insulating layer on a bottom portion of the trench and the second insulating layer on the sidewalls of the trench, wherein thickness of the third insulating layer on the sidewalls is thinner than that on the bottom of the trench. A control gate is formed on the third insulating layer in the trench.

Abstract: Nonvolatile memory devices including device isolation patterns on a semiconductor substrate are provided. The device isolation patterns define a cell active region and a peripheral active region of the semiconductor substrate. Cell gate electrodes are provided that cross over the cell active regions. Memory cell patterns are provided between the cell gate electrodes and the cell active regions and extend toward the device isolation patterns. A tunnel insulation film is provided between the memory cell pattern and the cell active region. Related methods of fabricating nonvolatile memory devices are also provided herein.

Abstract: Nonvolatile memory devices and related methods of manufacturing the same are provided. A nonvolatile memory device includes a tunneling layer on a substrate, a floating gate on the tunneling layer, an inter-gate dielectric layer structure on the floating gate, and a control gate on the inter-gate dielectric layer structure. The inter-gate dielectric layer structure includes a first silicon oxide layer, a high dielectric layer on the first silicon oxide layer, and a second silicon oxide layer on the high dielectric layer opposite to the first silicon oxide layer The high dielectric layer may include first and second high dielectric layers laminated on each other, and the first high dielectric layer may have a lower density of electron trap sites than the second high dielectric layer and may have a larger energy band gap or conduction band-offset than the second high dielectric layer.

Abstract: A manufacturing method of a semiconductor device of the present invention includes the steps of forming a stacked body in which a semiconductor film, a gate insulating film, and a first conductive film are sequentially stacked over a substrate; selectively removing the stacked body to form a plurality of island-shaped stacked bodies; forming an insulating film to cover the plurality of island-shaped stacked bodies; removing a part of the insulating film to expose a surface of the first conductive film, such that a surface of the first conductive film almost coextensive with a height of the insulating film; forming a second conductive film over the first conductive film and a left part of the insulating film; forming a resist over the second conductive film; selectively removing the first conductive film and the second conductive film using the resist as a mask.

Abstract: A metal oxide having a sufficiently higher dielectric constant than silicon nitride, such as Ti oxide, Zr oxide, or Hf oxide is used as base material, and in order to generate a trap level capable of moving in and out electrons therein, a high-valence substance of valence of 2 or more (that is, valence VI or higher) is added by a proper amount, and to control the trap level, a proper amount of nitrogen (carbon, boron, or low-valence substance) is added, and thus a nonvolatile semiconductor memory having a charge accumulating layer is obtained.

Abstract: A method and corresponding structure for shielding a floating gate tunneling element. The method comprises disposing a floating gate over a gate oxide using standard CMOS processing in two active areas defined by first and second doped well regions formed in a substrate surrounded by field oxide, and forming a floating gate shield layer so as to enclose the floating gate. The floating gate includes a first floating gate portion over an active area in the first doped well region and a second floating gate portion over the active area in the second doped well region. The first floating gate portion is substantially smaller than the second floating gate portion so as to enable adequate voltage coupling for Fowler-Nordheim tunneling to occur between the first doped well region and the first floating gate portion. The direction of tunneling is determined by high voltage application to one of the doped well regions.

Abstract: The present invention disclosed a non-volatile memory device and fabricating method thereof. The structure of non-volatile memory device at least comprises a substrate, several dielectric strips, several bit lines, a dielectrically stacking multi-layer, and several word lines. The substrate has several recesses. The dielectric strips are formed on the substrate, and each of the recess is interposed between two adjacent dielectric strips. The bit lines are respectively formed on the dielectric strips. The dielectrically stacking multi-layer comprising a charge-trapping layer is disposed on the bit lines and the recesses. The word lines are formed on the dielectrically stacking multi-layer and intersecting to the bit lines. When a voltage is applied to the bit lines, a plurality of inversion regions are respectively generated on the substrate.

Abstract: An electrically programmable device with embedded EEPROM and method for making thereof. The method includes providing a substrate including a first device region and a second device region, growing a first gate oxide layer in the first device region and the second device region, and forming a first diffusion region in the first device region and a second diffusion region and a third diffusion region in the second device region. Additionally, the method includes implanting a first plurality of ions to form a fourth diffusion region in the first device region and a fifth diffusion region in the second device region. The fourth diffusion region overlaps with the first diffusion region.

Abstract: Disclosed is a method of manufacturing a semiconductor device, including the steps of: forming on a second insulating film a first resist pattern having a first window; employing the first resist pattern as an etching mask to form first openings exposed from contact regions CR; forming, on a second conductive film, a second resist pattern having first resist portions; employing the second resist pattern as an etching mask to form first and second conductors, a floating gate and a control gate; forming a third resist pattern in regions I, II and III; and employing the third resist pattern as an etching mask to remove the portions of the second conductors under second windows.

Abstract: An electrically erasable programmable read-only memory (EEPROM) includes an access transistor having a floating gate and source/drain regions formed at opposite sides of the floating gate in a first well, a first well tap formed in the first well, a control gate located on a second region, first impurity regions formed at both sides of the control gate in the second region, and a second well tap formed in a third region. In order to erase information stored in a memory cell, a predetermined erasing voltage is applied to the source/drain regions of the access transistor and the first well tap, a ground voltage is applied to the first impurity regions in the second region, and a voltage, which is greater than 0V and less than a junction breakdown voltage between the active area and the first well, is applied to the second well tap.

Abstract: A memory cell in a nonvolatile semiconductor memory device includes a tunneling insulating film, a floating gate electrode made of a Si containing conductive material, an inter-electrode insulating film made of rare-earth oxide, rare-earth nitride or rare-earth oxynitride, a control gate electrode, and a metal silicide film formed between the floating gate electrode and the inter-electrode insulating film.

Abstract: A NAND-type non-volatile semiconductor memory device has a semiconductor substrate, an element isolation insulating film which is formed on a surface of the semiconductor substrate spaced apart at a predetermined distance from each other, a first insulating film which is formed between the element isolation insulating films on the semiconductor substrate, a floating gate which is formed on the first insulating films, a second insulating gate which is formed on an end region of the floating gate, a control gate which is formed on the second insulating film, and a contact plug which is formed on a surface of the floating gate so that one end of the contact plug is electrically connected to the control gate.

Abstract: A non-volatile memory device includes an active region in which a channel of a transistor is formed in a substrate, element isolation films defining the active region and formed on the substrate at both sides of the channel at a height lower than an upper surface of the active region, a first dielectric layer, a second dielectric layer, and a control gate electrode formed on the active region in this order, and a floating gate electrode formed between the first dielectric layer and the second dielectric layer so as to intersect the length direction of the channel and extend to the upper surfaces of the element isolation films at both sides of the channel, thereby surrounding the channel.

Abstract: A nonvolatile semiconductor memory device includes a gate portion formed by laminating a tunnel insulating film, floating gate electrode, inter-poly insulating film and control gate electrode on a semiconductor substrate, and source and drain regions formed on the substrate. The tunnel insulating film has a three-layered structure having a silicon nitride film sandwiched between silicon oxide films. The silicon nitride film is continuous in an in-plane direction and has 3-coordinate nitrogen bonds and at least one of second neighboring atoms of nitrogen is nitrogen.

Abstract: Devices and methods are provided with respect to a gate stack for a nonvolatile structure. According to one aspect, a gate stack is provided. One embodiment of the gate stack includes a tunnel medium, a high K charge blocking and charge storing medium, and an injector medium. The high K charge blocking and charge storing medium is disposed on the tunnel medium. The injector medium is operably disposed with respect to the tunnel medium and the high K charge blocking and charge storing medium to provide charge transport by enhanced tunneling. According to one embodiment, the injector medium is disposed on the high K charge blocking and charge storing medium. According to one embodiment, the tunnel medium is disposed on the injector medium. Other aspects and embodiments are provided herein.

Abstract: A nonvolatile semiconductor memory device includes: a semiconductor substrate; and a memory cell. The memory cell includes: a source region and a drain region formed at a distance from each other on the semiconductor substrate; a tunnel insulating film formed on a channel region of the semiconductor substrate, the channel region being located between the source region and the drain region; a charge storage film formed on the tunnel insulating film; a charge block film formed on the charge storage film; and a control electrode that is formed on the charge block film. The control electrode includes a Hf oxide film or a Zr oxide film having at least one element selected from the first group consisting of V, Cr, Mn, and Tc added thereto, and having at least one element selected from the second group consisting of F, H, and Ta added thereto.

Abstract: A method of fabricating a nonvolatile semiconductor memory device includes the steps of: (a) forming a layered dielectric film on the semiconductor substrate; (b) forming a first conductive film on the layered dielectric film; (c) forming a first dielectric film on the first conductive film; (d) patterning the first dielectric film and the first conductive film to form a layered pattern composed of first dielectric films and first conductive films; and (e) implanting a first impurity along a direction having an inclination angle to a normal direction to a principal plane of the semiconductor substrate by using the layered pattern as a mask to form a first impurity diffusion layer being the same in conductivity type as the semiconductor substrate, wherein, step (d) includes patterning the first dielectric film to form the first dielectric films having a shape with a width narrower in an upper surface than in a lower surface.

Abstract: A nonvolatile memory cell is disclosed, having first and second semiconductor islands at the same horizontal level and spaced a predetermined distance apart, the first semiconductor island providing a control gate and the second semiconductor island providing source and drain terminals; a gate dielectric layer on at least part of the first semiconductor island; a tunneling dielectric layer on at least part of the second semiconductor island; a floating gate on at least part of the gate dielectric layer and the tunneling dielectric layer; and a metal layer in electrical contact with the control gate and the source and drain terminals. In one advantageous embodiment, the nonvolatile memory cell may be manufactured using an “all-printed” process technology.

Abstract: Disclosed is a flash memory device and a method of manufacturing the same. The flash memory device includes a floating gate formed on a semiconductor substrate, a select gate self-aligned on one sidewall of the floating gate, and an ONO pattern interposed between the floating gate and the select gate. A self-aligned split gate structure is formed for an EEPROM tunnel oxide cell flash memory device employing a split gate structure, so that a cell current is constant and the erasing characteristic between cells is uniform, thereby improving the reliability.

Abstract: A semiconductor flash memory includes a tunnel oxide film formed over a semiconductor substrate, a first spacer composed of polysilicon formed over the semiconductor substrate including the tunnel oxide film, a second spacer composed of an insulating material formed at sidewalls of the first spacer, a dielectric film formed at the uppermost surface of the first spacer and the second spacer, a control gate formed at the uppermost surface of the dielectric film, and a third spacer composed of an insulating material formed at and contacting sidewalls of the second spacer, the dielectric film and the control gate. A first source/drain region formed may be formed in the semiconductor substrate and self-aligned with the first spacer and a second source/drain region may be formed in the semiconductor substrate and self-aligned with the second spacer.

Abstract: Etch stop structures for floating gate devices are generally described.

Abstract: Provided is a floating gate having multiple charge storing layers, a non-volatile memory device using the same, and a method of fabricating the floating gate and the non-volatile memory device, in which the multiple charge storing layers using metal nano-crystals of nano size is formed to thereby enhance a charge storage capacity of the memory device. The floating gate includes a polymer electrolytic film which is deposited on a tunneling oxide film, and is formed of at least one stage in which at least one thin film is deposited on each stage, and at least one metal nano-crystal film which is self-assembled on the upper surface of each stage of the polymer electrolytic film and on which a number of metal nano-crystals for trapping charges are deposited. The floating gate is made by self-assembling the metal nano-crystals on the polymer electrolytic film, and thus can be fabricated without undergoing a heat treatment process at high temperature.

Abstract: A floating gate memory cell has a floating gate in which there are two floating gate layers. The top layer is etched to provide a contour in the top layer while leaving the lower layer unchanged. The control gate follows the contour of the floating gate to increase capacitance therebetween. The two layers of the floating gate can be polysilicon separated by a very thin etch stop layer. This etch stop layer is thick enough to provide an etch stop during a polysilicon etch but preferably thin enough to be electrically transparent. Electrons are able to easily move between the two layers. Thus the etch of the top layer does not extend into the lower layer but the first and second layer have the electrical effect for the purposes of a floating gate of being a continuous conductive layer.

Abstract: A method of manufacturing a memory cell 200. The method comprises forming a memory stack 215. Forming the memory stack includes pre-treating an insulating layer 210 in a substantially ammonia atmosphere for a period of more than 5 minutes to thereby form a pre-treated insulating layer 310. Forming the memory stack also includes depositing a silicon nitride layer on the pre-treated insulating layer.

Abstract: A method of operating a non-volatile memory cell is described, including pre-erasing the cell through double-side biased (DSB) injection of a first type of carrier and programming the cell through Fowler-Nordheim (FN) tunneling of a second type of carrier.

Abstract: A nonvolatile semiconductor memory device capable of improving injection efficiency and simplifying manufacturing process is provided. The device comprises a memory cell having second conductive type of first impurity diffusion area and second impurity diffusion area on a first conductive type of semiconductor substrate, between the first and second impurity diffusion areas, a first laminate section formed by laminating a first insulating film, a charge storage layer, a second insulating film and a first gate electrode in this order from the bottom, and a second laminate section formed by laminating a third insulating film and a second gate electrode in this order from the bottom, wherein an area sandwiched between the first and second laminate sections is the second conductive type of a third impurity diffusion area having impurity density lower than that of the first and second impurity diffusion areas and not higher than 5×1012 ions/cm2.

Abstract: One or more embodiments, relate to a field effect transistor, comprising: a substrate; a gate stack disposed over the substrate, the gate stack comprising a gate electrode overlying a gate dielectric; and a sidewall spacer may be disposed over the substrate and laterally disposed from the gate stack, the spacer comprising a polysilicon material.

Abstract: A memory cell comprises a body of a semiconductor material having a first conductivity type. A conductor-filter system includes a first conductor having thermal charge carriers, and a filter contacting the first conductor and including dielectrics for providing a filtering function on the charge carriers of one polarity. The filter includes a first set of electrically alterable potential barriers. A conductor-insulator system includes a second conductor and a first insulator contacting the second conductor at an interface and having a second set of electrically alterable potential barriers. A first region is spaced-apart from the second conductor. A channel of the body is defined therebetween. A second insulator is adjacent to the first region. A charge storage region is disposed in between the first and the second insulators. A word-line has a first portion and a second portion comprising the first conductor disposed over and insulated from the body.

Abstract: A nonvolatile semiconductor memory device includes a plurality of nonvolatile memory cells formed on a semiconductor substrate, each memory cell including source and drain regions separately formed on a surface portion of the substrate, buried insulating films formed in portions of the substrate that lie under the source and drain regions and each having a dielectric constant smaller than that of the substrate, a tunnel insulating film formed on a channel region formed between the source and drain regions, a charge storage layer formed of a dielectric body on the tunnel insulating film, a block insulating film formed on the charge storage layer, and a control gate electrode formed on the block insulating film.

Abstract: A method for forming a flash memory cell and the structure thereof is disclosed. The flash memory cell includes a substrate, a first raised source/drain region and a second raised source/drain region separated by a trench in-between, a first charge-trapping spacer and a second charge-trapping spacer respectively on the sidewall of the first and second raised source/drain region, a gate structure covering the first and second spacers, the trench and the first and second raised source/drain regions and a gate oxide layer located between the gate structure and the first and second raised source/drain regions and the substrate. By forming the charge-trapping spacers with less e-distribution, the flash memory affords better erasure efficiency.

Abstract: A nonvolatile semiconductor storage device including a number of memory cells formed on a semiconductor substrate, each of the memory cells has a tunnel insulating film, a charge storage layer, a block insulating film, and a gate electrode which are formed in sequence on the substrate. The gate electrode is structured such that at least first and second gate electrode layers are stacked. The dimension in the direction of gate length of the second gate electrode layer, which is formed on the first gate electrode layer, is smaller than the dimension in the direction of gate length of the first gate electrode layer.