Abstract: A non-volatile semiconductor memory device comprises a plurality of memory cells, each including a semiconductor substrate, a first insulating film formed on the semiconductor substrate, a floating gate formed on the semiconductor substrate with the inclusion of the first insulating film, a second insulating film formed on the floating gate, and a control gate formed on the floating gate with the inclusion of the second insulating film; an element isolation insulating film formed in the semiconductor substrate and extending in a gate-length direction to isolate between memory cells adjoining in a gate-width direction; and an air gap formed on the element isolation insulating film and between floating gates adjoining in the gate-width direction.

Abstract: An electrically erasable programmable read only memory (EEPROM) cell structure and a method of fabricating the same. The EEPROM cell comprising a substrate comprising two shallow trench isolation (STI) structures separated by a substrate portion; an intermediate patterned layer formed on the substrate such that the patterned layer covers respective portions of each STI structure; a floating gate bridging between the STI structures such that the floating gate extends over the intermediate patterned layer; a dielectric layer formed over the floating gate; and a control gate formed over the dielectric layer.

Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a plurality of U-shaped memory strings, each of the plurality of U-shaped memory strings including a first columnar body, a second columnar body, and a conductive connection body. The conductive connection body connects the first columnar body and the second columnar body. A plurality of first memory cells are connected in series in the first columnar body and are composed of a plurality of first conductive layers, a first inter-gate insulating film, a plurality of first floating electrodes, a first tunnel insulating film, and a first memory channel layer. The plurality of first floating electrodes are separated from the plurality of first conductive layers by the first inter-gate insulating film. A plurality of second memory cells are connected in series in the second columnar body, similally to the plurality of first memory cells.

Abstract: A semiconductor device fabrication method includes forming a tunnel insulating film on a substrate containing silicon, forming a floating gate on the tunnel insulating film, forming an integral insulating film on the floating gate, and forming a control gate on the integral insulating film. The floating gate is formed on the tunnel insulating film by forming a seed layer containing amorphous silicon on the tunnel insulating film, forming an impurity later containing adsorbed boron or germanium on the seed layer, and forming a cap layer containing silicon on the impurity layer.

Abstract: A nonvolatile memory device includes a substrate; a channel layer projecting from a surface of the substrate, in a direction perpendicular to the surface; a tunnel dielectric layer surrounding the channel layer; a plurality of interlayer dielectric layers and a plurality of control gate electrodes alternately formed along the channel layer; floating gate electrodes interposed between the tunnel dielectric layer and the plurality of control gate electrodes, the floating gate electrodes comprising a metal-semiconductor compound; and a charge blocking layer interposed between each of the plurality of control gate electrodes and each of the plurality of floating gate electrodes.

Abstract: A method of manufacturing a semiconductor device comprising: forming a first insulating film on a semiconductor substrate; forming an adsorption film on the first insulating film; forming a first film containing germanium on the adsorption film; forming a second insulating film on the first film; forming a floating electrode film on the second insulating film; forming a third insulating film on the floating electrode film; and forming a gate electrode on the third insulating film.

Abstract: According to one embodiment, a semiconductor device includes a semiconductor substrate, a tunnel insulating film on the semiconductor substrate, a first floating gate electrode on the tunnel insulating film, an inter-floating gate insulating film on the first floating gate electrode, a second floating gate electrode on the inter-floating gate insulating film, an inter-electrode insulating film on the second floating gate electrode, and a control gate electrode on the inter-electrode insulating film. The inter-floating gate insulating film includes a main insulating film, and a first fixed charge layer between the main insulating film and the second floating gate electrode and having negative fixed charges.

Abstract: The present invention discloses a floating gate structure of a flash memory device and a method for fabricating the same, which relates to a nonvolatile memory in a manufacturing technology of an ultra-large-scaled integrated circuit. In the invention, by modifying a manufacturing of a floating gate in the a standard process for the flash memory, that is, by adding three steps of deposition, two steps of etching and one step of CMP, an -shaped floating gate is formed. In addition to these steps, all the other steps are the same as those of the standard process for the flash memory process. By the invention, a coupling ratio may be improved effectively and a crosstalk between adjacent devices may be lowered, without adding additional photomasks and barely increasing a process complexity, which are very important to improve programming speed and reliability.

Abstract: Provided are a method for manufacturing a memory device and a memory device manufactured by the method. The memory device may be a flash memory device. The method for manufacturing the memory device may include sequentially stacking a tunnel dielectric, a floating gate conductive layer, an inter-gate dielectric, and a control gate conductive layer on a semiconductor substrate; anisotropically etching the floating gate conductive layer, the inter-gate dielectric, and the control gate conductive layer to form gate structures. The gate structures may be separated by regions where top surfaces of the tunnel dielectric are exposed, the exposed top surfaces being damaged during formation of the gate structures. The method includes reacting the exposed top surfaces of the tunnel dielectric damaged during the formation of the gate structures with a reaction gas comprising ammonium fluoride to form a reaction by-product on the exposed top surfaces of the tunnel dielectric, and removing the reaction by-product.

Abstract: A semiconductor device and a method for manufacturing the same are provided. The semiconductor device includes a gate pattern formed by patterning a tunnel insulating layer, a conductive film for a floating gate, a dielectric film, a conductive film for a control gate, and a gate metal film sequentially formed on a semiconductor substrate; a first barrier film formed on side walls of the gate metal film; and a second barrier film formed on an upper surface of the gate metal film.

Abstract: Non-volatile memories and methods of fabrication thereof are described. In one embodiment, a method of fabricating a semiconductor device includes forming an oxide layer over a semiconductor substrate, and exposing the oxide layer to a first nitridation step to form a first nitrogen rich region. The first nitrogen rich region is disposed adjacent an interface between the oxide layer and the semiconductor substrate. After the first nitridation step, the oxide layer is exposed to a second nitridation step to form a second nitrogen rich region. A first gate electrode is formed on the oxide layer, wherein the second nitrogen rich region is disposed adjacent an interface between the oxide layer and the first gate electrode.

Abstract: A method of forming a plurality of spaced features includes forming sacrificial hardmask material over underlying material. The sacrificial hardmask material has at least two layers of different composition. Portions of the sacrificial hardmask material are removed to form a mask over the underlying material. Individual features of the mask have at least two layers of different composition, with one of the layers of each of the individual features having a tensile intrinsic stress of at least 400.0 MPa. The individual features have a total tensile intrinsic stress greater than 0.0 MPa. The mask is used while etching into the underlying material to form a plurality of spaced features comprising the underlying material. Other implementations are disclosed.

Abstract: In a manufacturing method of a flash memory structure with a stress area, a better stress effect can be achieved by controlling the manufacturing process of a tunneling oxide layer formed in a gate structure and contacted with a silicon substrate, so that an L-shaped spacer (or a first stress area) and a contact etch stop layer (or a second stress area) of each L-shaped spacer are formed between two gate structures and aligned towards each other to enhance the carrier mobility of the gate structure, so as to achieve the effects of improving a read current, obtaining the required read current by using a lower read voltage, reducing the possibility of having a stress-induced leakage current, and enhancing the data preservation of the flash memory.

Abstract: In a manufacturing method of a flash memory structure with a stress area, a better stress effect can be achieved by controlling the manufacturing process of a tunneling oxide layer formed in a gate structure and contacted with a silicon substrate, so that an L-shaped spacer (or a first stress area) and a contact etch stop layer (or a second stress area) of each L-shaped spacer are formed between two gate structures and aligned towards each other to enhance the carrier mobility of the gate structure, so as to achieve the effects of improving a read current, obtaining the required read current by using a lower read voltage, reducing the possibility of having a stress-induced leakage current, and enhancing the data preservation of the flash memory.

Abstract: A non-volatile semiconductor memory device comprises a plurality of memory cells, each including a semiconductor substrate, a first insulating film formed on the semiconductor substrate, a floating gate formed on the semiconductor substrate with the inclusion of the first insulating film, a second insulating film formed on the floating gate, and a control gate formed on the floating gate with the inclusion of the second insulating film; an element isolation insulating film formed in the semiconductor substrate and extending in a gate-length direction to isolate between memory cells adjoining in a gate-width direction; and an air gap formed on the element isolation insulating film and between floating gates adjoining in the gate-width direction.

Abstract: A non-volatile storage system includes memory cells with floating gates that comprises three layers separated by two dielectric layers (an upper dielectric layer and lower dielectric layer). The dielectric layers may be an oxide layers, nitride layers, combinations of oxide and nitride, or some other suitable dielectric material. The lower dielectric layer is close to the bottom of the floating gate (near interface between floating gate and tunnel dielectric), while the upper dielectric layer is close to top of the floating gate (near interface between floating gate and inter-gate dielectric).

Abstract: A nonvolatile memory device and a method of forming a nonvolatile memory device are provided. The nonvolatile memory device includes an active region of a semiconductor substrate defined by a device isolation layer, a tunnel insulating structure disposed on the active region, and a charge storage structure disposed on the tunnel insulating structure. The nonvolatile memory device also includes a gate interlayer dielectric layer disposed on the charge storage structure, and a control gate electrode disposed on the gate interlayer dielectric layer. The charge storage structure includes an upper charge storage structure and a lower charge storage structure, and the upper charge storage structure has a higher impurity concentration than the lower charge storage structure.

Abstract: According to one embodiment, a semiconductor memory device includes a semiconductor substrate, a tunnel insulating film, a first electrode, an interelectrode insulating film and a second electrode. The tunnel insulating film is provided on the semiconductor substrate. The first electrode is provided on the tunnel insulating film. The interelectrode insulating film is provided on the first electrode. The second electrode is provided on the interelectrode insulating film. The interelectrode insulating film includes a stacked insulating layer, a charge storage layer and a block insulating layer. The charge storage layer is provided on the stacked insulating layer. The block insulating layer is provided on the charge storage layer. The stacked insulating layer includes a first insulating layer, a quantum effect layer and a second insulating layer. The quantum effect layer is provided on the first insulating layer. The second insulating layer is provided on the quantum effect layer.

Abstract: A method of fabricating a semiconductor device including forming a charge storage layer, and forming a first tunnel insulating layer covering the charge storage layer, the forming of the first tunnel insulating layer including heat treating the charge storage layer.

Abstract: A method of manufacturing a semiconductor device, the method including forming a tunnel insulating layer on an upper surface of a substrate, forming gate patterns on an upper surface of the tunnel insulating layer, forming capping layer patterns on sidewalls of the gate patterns and on the upper surface of the tunnel insulating layer, etching a portion of the tunnel insulating layer that is not covered with the gate patterns or the capping layer patterns to form a tunnel insulating layer pattern, and forming a first insulating layer on the upper surface of the substrate to cover the gate patterns, the capping layer patterns, and the tunnel insulating layer pattern, wherein the first insulating layer has an air gap between the capping layer patterns.

Abstract: Monolithic three dimensional NAND strings and methods of making. The method includes both front side and back side processing. Using the combination of front side and back side processing, a NAND string can be formed that includes an air gap between the floating gates in the NAND string. The NAND string may be formed with a single vertical channel. Alternatively, the NAND string may have a U shape with two vertical channels connected with a horizontal channel.

Abstract: A nonvolatile semiconductor memory device includes: forming a stacked body by alternately stacking a plurality of interlayer insulating films and a plurality of control gate electrodes; forming a through-hole extending in a stacking direction in the stacked body; etching a portion of the interlayer insulating film facing the through-hole via the through-hole to remove the portion; forming a removed portion; forming a first insulating film on inner faces of the through-hole and the portion in which the interlayer insulating films are removed; forming a floating gate electrode in the portion in which the interlayer insulating films are removed; forming a second insulating film so as to cover a portion of the floating gate electrode facing the through-hole; and burying a semiconductor pillar in the through-hole.

Abstract: According to one embodiment, a method of manufacturing a semiconductor device is provided. In the method, a tunnel insulating film and a first conductive film are formed on a semiconductor layer. A trench is formed. A first sacrifice film is buried in the trench. A second sacrifice film having density higher than that of the first sacrifice film is formed on the first sacrifice film in the trench. An insulating film is formed on the first conductive film and the second sacrifice film. A second conductive film is formed on the insulating film. The second sacrifice film is exposed. The first sacrifice film and the second sacrifice film are removed.

Abstract: A high dielectric constant (high-k) gate dielectric for a field effect transistor (FET) and a high-k tunnel dielectric for a non-volatile random access memory (NVRAM) device are simultaneously formed on a semiconductor substrate. A stack of at least one conductive material layer, a control gate dielectric layer, and a disposable material layer is subsequently deposited and lithographically patterned. A planarization dielectric layer is deposited and patterned, and disposable material portions are removed. A remaining portion of the control gate dielectric layer is preserved in the NVRAM device region, but is removed in the FET region. A conductive material is deposited in gate cavities to provide a control gate for the NVRAM device and a gate portion for the FET. Alternately, the control gate dielectric layer may replaced with a high-k control gate dielectric in the NVRAM device region.

Abstract: The present invention discloses a floating gate structure of a flash memory device and a method for fabricating the same, which relates to a nonvolatile memory in a manufacturing technology of an ultra-large-scaled integrated circuit. In the invention, by modifying a manufacturing of a floating gate in the a standard process for the flash memory, that is, by adding three steps of deposition, two steps of etching and one step of CMP, an I-shaped floating gate is formed. In addition to these steps, all the other steps are the same as those of the standard process for the flash memory process. By the invention, a coupling ratio may be improved effectively and a crosstalk between adjacent devices may be lowered, without adding additional photomasks and barely increasing a process complexity, which are very important to improve programming speed and reliability.

Abstract: Monolithic, three dimensional NAND strings include a semiconductor channel, at least one end portion of the semiconductor channel extending substantially perpendicular to a major surface of a substrate, a plurality of control gate electrodes having a strip shape extending substantially parallel to the major surface of the substrate, the blocking dielectric comprising a plurality of blocking dielectric segments, a plurality of discrete charge storage segments, and a tunnel dielectric located between each one of the plurality of the discrete charge storage segments and the semiconductor channel.

Abstract: A gate structure includes an insulation layer on a substrate, a first conductive layer pattern on the insulation layer, a metal ohmic layer pattern on the first conductive layer pattern, a diffusion reduction layer pattern on the metal ohmic layer pattern an amorphous layer pattern on the diffusion reduction layer pattern, and a second conductive layer pattern on the amorphous layer pattern. The gate structure may have a low sheet resistance and desired thermal stability.

Abstract: Methods of forming semiconductor device structures are disclosed. One method comprises forming a plurality of loops of a conductive material. Each loop of the plurality of loops comprises a uniform pattern. In one embodiment, a portion of the conductive material is removed from at least one location in each loop of the plurality of loops. Contacts are formed to the conductive material. A semiconductor device structure is also disclosed.

Abstract: Nanostructure-based charge storage regions are included in non-volatile memory devices and integrated with the fabrication of select gates and peripheral circuitry. One or more nanostructure coatings are applied over a substrate at a memory array area and a peripheral circuitry area. Various processes for removing the nanostructure coating from undesired areas of the substrate, such as target areas for select gates and peripheral transistors, are provided. One or more nanostructure coatings are formed using self-assembly based processes to selectively form nanostructures over active areas of the substrate in one example. Self-assembly permits the formation of discrete lines of nanostructures that are electrically isolated from one another without requiring patterning or etching of the nanostructure coating.

Abstract: A conductive layer may be fabricated on a semiconductor substrate by loading a silicon substrate in to a chamber whose inside temperature is at a loading temperature in the range of approximately 250° C. to approximately 300° C., increasing the inside temperature of the chamber from the loading temperature to a process temperature, and sequentially stacking a single crystalline silicon layer and a polycrystalline silicon layer over the silicon substrate by supplying a silicon source gas and an impurity source gas in to the chamber, where the chamber may be, for example, a CVD chamber or a LPCVD chamber.

Abstract: A floating gate device is provided. A tunnel oxide layer is formed over the channel. A floating gate is formed over the tunnel oxide layer. A high-k dielectric layer is formed over the floating gate. A control gate is formed over the high-k dielectric layer. At least one of the control gate and/or the floating gate includes an oxygen scavenging element. The oxygen scavenging element is configured to decrease an oxygen density at least one of at a first interface between the control gate and the high-k dielectric layer, at a second interface between the high-k dielectric layer and the floating gate, at a third interface between the floating gate and the tunnel oxide layer, and at a fourth interface between the tunnel oxide layer and the channel responsive to annealing.

Abstract: Methods of fabricating 3D charge-trap memory cells are described, along with apparatus and systems that include them. In a planar stack formed by alternate layers of electrically conductive and insulating material, a substantially vertical opening may be formed. Inside the vertical opening a substantially vertical structure may be formed that comprises a first layer, a charge-trap layer, a tunneling oxide layer, and an epitaxial silicon portion. Additional embodiments are also described.

Abstract: A method for forming a memory device includes: forming a tunnel insulation layer, a conductive layer for a floating gate electrode, a charge blocking layer and a conductive layer for a control gate electrode over a substrate; and selectively etching the conductive layer for the control gate electrode, the charge blocking layer and the conductive layer for the floating gate electrode, thereby forming a plurality of gate lines, a plurality of select lines and at least two dummy lines disposed in a gap region between adjacent select lines, wherein the gate lines, the select lines and the dummy lines together construct strings.

Abstract: Patterns of a nonvolatile memory device include a semiconductor substrate that defines active regions extending in a longitudinal direction, an isolation structure formed between the active regions, a tunnel insulating layer formed on the active regions, a charge trap layer formed on the tunnel insulating layer, a first dielectric layer formed on the charge trap layer and the isolation structure, wherein the first dielectric layers is extended along a lateral direction, a control gate layer formed on the first dielectric layer, wherein the control gate layer is extended along the lateral direction, and a second dielectric layer formed on a sidewall of the control gate layer along the lateral direction and coupled to the first dielectric layer.

Abstract: A method of forming gate patterns of a nonvolatile memory device comprises forming stack patterns each having an insulating layer and a conductive layer stacked over a semiconductor substrate, and forming an anti-oxidation layer on sidewalls of the insulating layer by selectively nitrifying the insulating layer.

Abstract: A method of manufacturing a nonvolatile memory device comprises providing a semiconductor substrate defining active regions and isolation regions with a gate insulating layer and a floating gate formed over each active region and isolation layer formed in the respective isolation regions, forming a dielectric layer on a surface of the isolation layers and the floating gates, forming a polysilicon layer over the dielectric layer through a polysilicon deposition process using a nitrogen source gas, a silicon source gas, and an impurity doping gas, and patterning the polysilicon layer to form a control gate.

Abstract: There are provided a semiconductor device and a fabrication method therefor including an ONO film (18) formed on a semiconductor substrate (10), a word line (24) formed on the ONO film (18), a bit line (20) formed in the semiconductor substrate (10), and a conductive layer (32) that is in contact with the bit line (20), runs in a length direction of the bit line (20), and includes a polysilicon layer or a metal layer. In accordance with the present invention, a semiconductor device and a fabrication method therefor are provided wherein degradation of the writing and erasing characteristics and degradation of the transistor characteristics such as a junction leakage are suppressed, and the bit line resistance is decreased.

Abstract: A nonvolatile memory device includes a substrate having active regions that are defined by an isolation layer and that have first sidewalls extending upward from the isolation layer, floating gates adjoining the first sidewalls of the active regions with a tunnel dielectric layer interposed between the active regions and the floating gates and extending upward from the substrate, an intergate dielectric layer disposed over the floating gates, and control gates disposed over the intergate dielectric layer.

Abstract: A non-volatile memory device includes a plurality of stacked patterns where a tunnel insulation layer, a floating gate, and a dielectric layer are sequentially stacked over a substrate, trenches formed in the substrate between the stacked patterns, an isolation layer gap-filling the trenches and space between the stacked patterns, and a control gate formed over the dielectric layer.

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 silicon dioxide film fabricating process includes the following steps. Firstly, a substrate is provided. A rapid thermal oxidation-in situ steam generation process is performed to form a silicon dioxide film on the substrate. An annealing process is performed to anneal the substrate in a first gas mixture at a temperature in the range of 1000° C. to 1100° C.

Abstract: A non-volatile memory device includes a peripheral circuit region and a cell region. A method for fabricating the non-volatile memory device includes forming gate patterns over a substrate, the gate pattern including a tunnel insulation layer, a floating gate electrode, a charge blocking layer and a control gate electrode, and removing the control gate electrode and the charge blocking layer of the gate pattern formed in the peripheral circuit region.

Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a substrate, a tunneling insulating film, a floating gate, a leak suppression unit, an inter-gate insulating film, and a control gate. The substrate includes silicon. The tunneling insulating film is provided on the substrate. The floating gate is provided on the tunneling insulating film. The leak suppression unit is provided on the floating gate. The inter-gate insulating film is provided on the leak suppression unit. The control gate is provided on the inter-gate insulating film. The dielectric constant of the leak suppression unit is higher than a dielectric constant of the inter-gate insulating film.

Abstract: Monolithic, three dimensional NAND strings include a semiconductor channel, at least one end portion of the semiconductor channel extending substantially perpendicular to a major surface of a substrate, a plurality of control gate electrodes having a strip shape extending substantially parallel to the major surface of the substrate, the blocking dielectric comprising a plurality of blocking dielectric segments, a plurality of discrete charge storage segments, and a tunnel dielectric located between each one of the plurality of the discrete charge storage segments and the semiconductor channel.

Abstract: A nonvolatile semiconductor memory device includes: a semiconductor member; a memory film provided on a surface of the semiconductor member and being capable of storing charge; and a plurality of control gate electrodes provided on the memory film, spaced from each other, and arranged along a direction parallel to the surface. Average dielectric constant of a material interposed between one of the control gate electrodes and a portion of the semiconductor member located immediately below the control gate electrode adjacent to the one control gate electrode is lower than average dielectric constant of a material interposed between the one control gate electrode and a portion of the semiconductor member located immediately below the one control gate electrode.

Abstract: A semiconductor device includes a semiconductor island having at least one electrical dopant atom and encapsulated by dielectric materials including at least one dielectric material layer. At least two portions of the at least one dielectric material layer have a thickness less than 2 nm to enable quantum tunneling effects. A source-side conductive material portion and a drain-side conductive material portion abuts the two portions of the at least one dielectric material layer. A gate conductor is located on the at least one dielectric material layer between the source-side conductive material portion and the drain-side conductive material portion. The potential of the semiconductor island responds to the voltage at the gate conductor to enable or disable tunneling current through the two portions of the at least one dielectric material layer. Design structures for the semiconductor device are also provided.

Abstract: A manufacturing method of a semiconductor memory device includes forming a first gate electrode having a charge storage layer, a block layer, and a control gate electrode on a first region of a semiconductor substrate, forming a second gate electrode on a second region of the semiconductor substrate, forming a protective insulating film on a side surface of the block layer, exposing the first region while covering the second region on the semiconductor substrate with a photoresist, using the photoresist, the first gate electrode, and the protective insulating film as masks to implant an impurity into the first region of the semiconductor substrate, and removing the photoresist by wet etching which uses a mixed solution containing H2SO4 and H2O2. The protective insulating film having an etching selective ratio of 1:100 or above with respect to the photoresist under wet etching conditions using the mixed solution.

Abstract: According to one embodiment, a method is disclosed for manufacturing a nonvolatile memory device. The method can include forming a second stacked body, removing the second stacked body formed in a region where a first memory unit will be formed, forming a first stacked body, and removing the first stacked body formed in a region where a second memory unit will be formed. The method can include simultaneously processing the first stacked body formed in a region where the first memory unit will be formed and the second stacked body formed in a region where the second memory unit will be formed to form a memory cell of the first memory unit from the first stacked body and form a memory cell of the second memory unit from the second stacked body.

Abstract: Methods of fabricating a silicon oxide layer using an inorganic silicon precursor and methods of fabricating a semiconductor device using the same are provided. The methods of fabricating a semiconductor device include forming a tunnel insulating layer and a charge storage layer on a substrate; forming a dielectric layer structure on the charge storage layer using an atomic layer deposition (ALD) method, the dielectric layer structure including a first dielectric layer formed of silicon oxide, a second dielectric layer on the first dielectric layer formed of a material different from the material forming the first dielectric layer, and a third dielectric layer formed of the silicon oxide on the second dielectric layer; and forming a control gate on the dielectric layer structure.

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.