Abstract: A polysilicon thin film transistor, a manufacturing method thereof, an array substrate involve display technology field, and can repair the boundary defect and the defect state in polysilicon, suppress the hot carrier effect and make the characteristics of TFTs more stable. The polysilicon thin film transistor includes a gate electrode, a source electrode, a drain electrode and an active layer, the active layer comprises at least a channel area, first doped regions, second doped regions and heavily doped regions, and the first doped regions are disposed on two sides of the channel area, the second doped regions are disposed on sides of the first doped regions away from the channel area; the heavily doped regions are disposed on sides of the second doped regions opposed to the first doped regions; and dosage of ions in the heavily doped regions lies between that in the first doped regions and that in the second doped regions.

Abstract: A method for forming a semiconductor structure includes forming at least one fin on a semiconductor substrate. The least one fin includes a semiconducting material. A gate is formed over and in contact with the at least one fin. A germanium comprising layer is formed over and in contact with the at least one fin. Germanium from the germanium comprising layer is diffused into the semiconducting material of the at least one fin.

Abstract: A semiconductor structure includes a varactor and a field effect transistor. The varactor includes a body region that includes a semiconductor material and a first gate structure over the body region. The body region is doped to have a first conductivity type. The first gate structure includes a first gate insulation layer and a first work function adjustment metal layer. The field effect transistor includes a source region, a channel region, a drain region and a second gate structure over the channel region. The source region and the drain region are doped to have a second conductivity type that is opposite to the first conductivity type. The second gate structure includes a second gate insulation layer and a second work function adjustment metal layer. The first work function adjustment metal layer and the second work function adjustment metal layer include substantially the same metal.

Abstract: A method for forming strained fins includes etching trenches in a bulk substrate to form fins, filling the trenches with a dielectric fill and recessing the dielectric fill into the trenches to form shallow trench isolation regions. The fins are etched above the shallow trench isolation regions to form a staircase fin structure with narrow top portions of the fins. Gate structures are formed over the top portions of the fins. Raised source ad drain regions are epitaxially grown on opposite sides of the gate structure. A pre-morphization implant is performed to generate defects in the substrate to couple strain into the top portions of the fins.

Abstract: Semiconductor devices and methods of fabricating semiconductor devices are provided. The methods may include forming an interlayer insulation layer on a substrate. The interlayer insulation layer may surround a dummy silicon gate and may expose a top surface of the dummy silicon gate. The methods may also include recessing a portion of the interlayer insulation layer such that a portion of the dummy silicon gate protrudes above a top surface of the recessed interlayer insulation layer and forming an etch stop layer on the recessed interlayer insulation layer. A top surface of the etch stop layer may be coplanarly positioned with the top surface of the dummy silicon gate. The methods may further include forming a trench exposing the substrate by removing the dummy silicon gate using the etch stop layer as a mask.

Abstract: A method for fabricating a semiconductor device includes: implanting a first species into a substrate at a cold temperature to form a first region; and implanting a second species into the substrate at a hot temperature to form a second region that is adjacent to the first region.

Abstract: Methods are providing for fabricating transistors having at least one source region or drain region with a stressed portion. The methods include: forming, within a cavity of a substrate structure, the at least one source region or drain region with the internal stress; and resurfacing the at least one source region or drain region to reduce surface defects of the at least one source region or drain region without relaxing the stressed portion thereof. For instance, the resurfacing can include melting an upper portion of the at least one source region or drain region. In addition, the resurfacing can include re-crystallizing an upper portion of the at least one source region or drain region, and/or providing the at least one source region or drain region with at least one {111} surface.

Abstract: A method of forming a patterned hark mask layer includes the following steps. A semiconductor substrate is provided. An amorphous silicon layer is formed on the semiconductor substrate. An implantation process is performed on the amorphous silicon layer. An annealing treatment is performed on the amorphous silicon layer after the implantation process. A patterned hard mask layer is formed on the amorphous silicon layer after the annealing treatment.

Abstract: According to one embodiment, a semiconductor device includes a semiconductor substrate with a groove for forming an embedded gate therein, and a gate electrode embedded via a gate insulator film in the groove. A portion of the semiconductor substrate near the gate electrode is doped with a chemical element which is inactive in the semiconductor substrate.

Abstract: Methods of forming a semiconductor layer including germanium with low defectivity are provided. The methods may include sequentially forming a silicate glass layer, a diffusion barrier layer including nitride and an interfacial layer including oxide on a substrate. The methods may also include forming a first semiconductor layer on the interfacial layer and converting a portion of the first semiconductor layer into a second semiconductor layer having a germanium concentration therein that is higher than a germanium concentration of the first semiconductor layer.

Abstract: In aspects of the present invention, a method of forming a semiconductor device is disclosed, wherein amorphous regions are formed at an early stage during fabrication and the amorphous regions are conserved during subsequent processing sequences, and an intermediate semiconductor device structure with amorphous regions are provided at an early stage during fabrication. Herein a gate structure is provided over a semiconductor substrate and amorphous regions are formed adjacent the gate structure. Source/drain extension regions or source/drain regions are formed in the amorphous regions. In some illustrative embodiments, fluorine may be implanted into the amorphous regions. After the source/drain extension regions and/or the source/drain regions are formed, a rapid thermal anneal process is performed.

Abstract: This invention relates to a method for manufacturing a semiconductor device and semiconductor manufactured thereby, including growing, from a seed island mesa, an abrupt hetero-junction comprising a semiconductor crystal with few crystal defects on a dissimilar substrate that can be used as light emitting and photovoltaic device.

Abstract: A method for fabricating an apparatus using radiation annealing includes forming an annealable layer on a substrate. A radiation absorbing layer is also formed on the substrate, wherein the radiation absorbing layer heats up In response to radiation, and the radiation absorbing layer is formed adjacent to at least a portion of the annealable layer and non-adjacent to a portion of the apparatus. Radiation is directed toward the apparatus to heat up the radiation absorbing layer to anneal the at least a portion of the annealable layer that is adjacent to the radiation absorbing layer without annealing the portion of the apparatus that is non-adjacent to the radiation absorbing layer.

Abstract: Methods of forming a semiconductor device structure at advanced technology nodes and respective semiconductor device structures are provided at advanced technology nodes, i.e., smaller than 100 nm. In some illustrative embodiments, a fluorine implantation process for implanting fluorine at least into a polysilicon layer formed over a dielectric layer structure is performed prior to patterning the gate dielectric layer structure and the polysilicon layer for forming a gate structure and implanting source and drain regions at opposing sides of the gate structure.

Abstract: A material stack including an ohmic contact layer and a single crystalline semiconductor base substrate of a first conductivity type and having a surface Fermi level pinned close to a band edge (either the conduction band or valence band) is first provided. A stressor layer is then formed above the ohmic contact layer and a material portion of the single crystalline semiconductor base substrate is removed by a process referred to as spalling. A transparent conductive oxide layer is then formed on an exposed surface of the material portion of the single crystalline semiconductor base substrate that was removed by spalling.

Abstract: After formation of a silicon Fin part on a silicon substrate, a thin film including an impurity atom which becomes a donor or an acceptor is formed so that a thickness of the thin film formed on the surface of an upper flat portion of the silicon Fin part becomes large relative to a thickness of the thin film formed to the surface of side wall portions of the silicon Fin part. A first diagonal ion implantation from a diagonal upper direction to the thin film is performed and subsequently a second diagonal ion implantation is performed from an opposite diagonal upper direction to the thin film. Recoiling of the impurity atom from the inside of the thin film to the inside of the side wall portions and to the inside of the upper flat portion is realized by performing the first and second diagonal ion implantations.

Abstract: A method for fabricating a dual damascene metal gate includes forming a dummy gate onto a substrate, disposing a protective layer on the substrate and the dummy gate, and growing an expanding layer on sides of the dummy gate. The method further includes removing the protective layer, forming a spacer around the dummy gate, and depositing and planarizing a dielectric layer. The method further includes selectively removing the expanding layer, and removing the dummy gate.

Abstract: Methods for forming an electronic device having a fluorine-stabilized semiconductor substrate surface are disclosed. In an exemplary embodiment, a layer of a high-? dielectric material is formed together with a layer containing fluorine on a semiconductor substrate. Subsequent annealing causes the fluorine to migrate to the surface of the semiconductor (for example, silicon, germanium, or silicon-germanium). A thin interlayer of a semiconductor oxide may also be present at the semiconductor surface. The fluorine-containing layer can comprise F-containing WSix formed by ALD from WF6 and SiH4 precursor gases. A precise amount of F can be provided, sufficient to bind to substantially all of the dangling semiconductor atoms at the surface of the semiconductor substrate and sufficient to displace substantially all of the hydrogen atoms present at the surface of the semiconductor substrate.

Abstract: Multiple transistor types are formed in a common epitaxial layer by differential out-diffusion from a doped underlayer. Differential out-diffusion affects the thickness of a FET channel, the doping concentration in the FET channel, and distance between the gate dielectric layer and the doped underlayer. Differential out-diffusion may be achieved by differentially applying a dopant migration suppressor such as carbon; differentially doping the underlayer with two or more dopants having the same conductivity type but different diffusivities; and/or differentially applying thermal energy.

Abstract: The thickness of drain and source areas may be reduced by a cavity etch used for refilling the cavities with an appropriate semiconductor material, wherein, prior to the epitaxial growth, an implantation process may be performed so as to allow the formation of deep drain and source areas without contributing to unwanted channel doping for a given critical gate height. In other cases, the effective ion blocking length of the gate electrode structure may be enhanced by performing a tilted implantation step for incorporating deep drain and source regions.

Abstract: Embodiment of the present invention provides a method of forming a semiconductor device. The method includes providing a semiconductor substrate; epitaxially growing a silicon-carbon layer on top of the semiconductor substrate; amorphizing the silicon-carbon layer; covering the amorphized silicon-carbon layer with a stress liner; and subjecting the amorphized silicon-carbon layer to a solid phase epitaxy (SPE) process to form a highly substitutional silicon-carbon film. In one embodiment, the highly substitutional silicon-carbon film is formed to be embedded stressors in the source/drain regions of an nFET transistor, and provides tensile stress to a channel region of the nFET transistor for performance enhancement.

Abstract: A semiconductor device according to an embodiment includes a silicon carbide, a metal silicide formed on the silicon carbide and including a first layer and a second layer having a carbon ratio lower than that of the first layer, and a metallic electrode formed on the metal silicide, wherein the second layer is formed on the first layer, and the second layer is in contact with the metallic electrode, and an average grain diameter of a metal silicide in the second layer is larger than an average grain diameter of a metal silicide in the first layer.

Abstract: Multiple transistor types are formed in a common epitaxial layer by differential out-diffusion from a doped underlayer. Differential out-diffusion affects the thickness of a FET channel, the doping concentration in the FET channel, and distance between the gate dielectric layer and the doped underlayer. Differential out-diffusion may be achieved by differentially applying a dopant migration suppressor such as carbon; differentially doping the underlayer with two or more dopants having the same conductivity type but different diffusivities; and/or differentially applying thermal energy.

Abstract: Multiple transistor types are formed in a common epitaxial layer by differential out-diffusion from a doped underlayer. Differential out-diffusion affects the thickness of a FET channel, the doping concentration in the FET channel, and distance between the gate dielectric layer and the doped underlayer. Differential out-diffusion may be achieved by differentially applying a dopant migration suppressor such as carbon; differentially doping the underlayer with two or more dopants having the same conductivity type but different diffusivities; and/or differentially applying thermal energy.

Abstract: A vertical transient voltage suppressing (TVS) device includes a semiconductor substrate of a first conductivity type where the substrate is heavily doped, an epitaxial layer of the first conductivity type formed on the substrate where the epitaxial layer has a first thickness, and a base region of a second conductivity type formed in the epitaxial layer where the base region is positioned in a middle region of the epitaxial layer. The base region and the epitaxial layer provide a substantially symmetrical vertical doping profile on both sides of the base region. In one embodiment, the base region is formed by high energy implantation. In another embodiment, the base region is formed as a buried layer. The doping concentrations of the epitaxial layer and the base region are selected to configure the TVS device as a punchthrough diode based TVS or an avalanche mode TVS.

Abstract: A method of fabricating a semiconductor device includes providing a semiconductor substrate including a channel region, forming a gate electrode structure on the channel region of the semiconductor substrate, forming a first trench in the semiconductor substrate, and forming a second trench in the semiconductor device. The first trench may include a first tip that protrudes toward the channel. The second trench may be an enlargement of the first trench and may include a second tip that also protrudes toward the channel region. In some examples, the second tip may protrude further towards the channel region than the first tip.

Abstract: Devices are formed with boot shaped source/drain regions formed by isotropic etching followed by anisotropic etching. Embodiments include forming a gate on a substrate, forming a first spacer on each side of the gate, forming a source/drain region in the substrate on each side of the gate, wherein each source/drain region extends under a first spacer, but is separated therefrom by a portion of the substrate, and has a substantially horizontal bottom surface. Embodiments also include forming each source/drain region by forming a cavity to a first depth adjacent the first spacer and forming a second cavity to a second depth below the first cavity and extending laterally underneath the first spacers.

Abstract: A method includes epitaxially growing a germanium (Ge) layer onto a Ge substrate and incorporating a compensating species with a compensating atomic radius into the Ge layer. The method includes implanting an n-type dopant species with a dopant atomic radius into the Ge layer. The method includes selecting the n-type dopant species and the compensating species in such manner that the size of the Ge atomic radius is inbetween the n-type dopant atomic radius and the compensating atomic radius.

Abstract: In conventional processes, a recombination rate of minority carrier accumulated between a diffusion layer of an anode and a diffusion layer of a cathode cannot be enhanced. An interlayer insulating film 20 is formed on a semiconductor substrate 10. An opening 22 (first opening), an opening 24 (second opening) and an opening 26 are formed in the interlayer insulating film 20. The opening 22 and the opening 26 are formed above respective the p-type diffusion layer 16 and the n-type diffusion layer 18. The opening 24 is formed above the gap region that is a region between the p-type diffusion layer 16 and the n-type diffusion layer 18. A contact plug 32, a contact plug 34 and a contact plug 36 are embedded in the opening 22, the opening 24 and the opening 26 respectively. Both regions of the semiconductor substrate 10 located under the opening 22 among and located under the opening 24 are doped with an impurity.

Abstract: A method of modifying a shape of a cavity in a substrate. The method includes forming one or more cavities on a surface of the substrate between adjacent relief structures. The method also includes directing ions toward the substrate at a non-normal angle of incidence, wherein the ions strike an upper portion of a cavity sidewall, and wherein the ions do not strike a lower portion of the cavity sidewall. The method further includes etching the one or more cavities wherein the upper portion of a cavity sidewall etches more slowly than the lower portion of the sidewall cavity.

Abstract: A method is demonstrated to manufacture SOI substrates with high throughput while resources can be effectively used. The present invention is characterized by the feature in which the following process A and process B are repeated. The process A includes irradiation of a surface of a semiconductor wafer with cluster ions to form a separation layer in the semiconductor wafer. The semiconductor wafer and a substrate having an insulating surface are then overlapped with each other and bonded, which is followed by thermal treatment to separate the semiconductor wafer at or around the separation layer. A separation wafer and an SOT substrate which has a crystalline semiconductor layer over the substrate having the insulating surface are simultaneously obtained by the process A. The process B includes treatment of the separation wafer for reusing, which allows the separation wafer to be successively subjected to the process A.

Abstract: Post programming resistance of a semiconductor fuse is enhanced by using an implantation to form an amorphous silicon layer and to break up an underlying high-?/metal gate. Embodiments include forming a shallow trench isolation (STI) region in a silicon substrate, forming a high-? dielectric layer on the STI region, forming a metal gate on the high-? dielectric layer, forming a polysilicon layer over the metal gate, performing an implantation to convert the polysilicon layer into an amorphous silicon layer, wherein the implantation breaks up the metal gate, and forming a silicide on the amorphous silicon layer. By breaking up the metal gate, electrical connection of the fuse contacts through the metal gate is eliminated.

Abstract: A semiconductor device according to an embodiment includes a silicon carbide, a metal silicide formed on the silicon carbide and including a first layer and a second layer having a carbon ratio lower than that of the first layer, and a metallic electrode formed on the metal silicide, wherein the second layer is formed on the first layer, and the second layer is in contact with the metallic electrode, and an average grain diameter of a metal silicide in the second layer is larger than an average grain diameter of a metal silicide in the first layer.

Abstract: A silicon carbide substrate having a surface is prepared. A coating film made of a first material is formed directly on the surface of the silicon carbide substrate. A mask layer made of a second material is formed on the coating film. The first material is higher in adhesiveness with silicon carbide than the second material. A first opening is formed in the mask layer. First impurity ions for providing a first conductivity type are implanted into the silicon carbide substrate by using ion beams passing through the first opening in the mask layer and through the coating film.

Abstract: A method for manufacturing a SiC semiconductor device includes: a step of forming an oxide film on a surface of a SiC substrate; and a step of removing the oxide film. In the step of forming the oxide film, ozone gas is used. In the step of removing the oxide film, it is preferable to use halogen plasma or hydrogen plasma. In this way, problems associated with a chemical solution can be reduced while obtaining a method and device for manufacturing a SiC semiconductor device, by each of which a cleaning effect can be improved.

Abstract: A silicon carbide substrate having a surface is prepared. An impurity region is formed by implanting ions from the surface into the silicon carbide substrate. Annealing for activating the impurity region is performed. The annealing includes the step of applying first laser light having a first wavelength to the surface of the silicon carbide substrate, and the step of applying second laser light having a second wavelength to the surface of the silicon carbide substrate. The silicon carbide substrate has first and second extinction coefficients at the first and second wavelengths, respectively. A ratio of the first extinction coefficient to the first wavelength is higher than 5×105/m. A ratio of the second extinction coefficient to the second wavelength is lower than 5×105/m. Consequently, damage to the surface of the silicon carbide substrate during laser annealing can be reduced.

Abstract: Described herein are methods for forming a semiconductor structure. The methods involve forming a doped semiconductor film, amorphizing the doped semiconductor film through ion implantation; and annealing the doped semiconductor film. The ion implantation and the annealing can increase an activation efficiency of the dopant. The ion implantation and the annealing can also reduce a number of crystalline defects in the doped semiconductor film.

Abstract: An impurity of a first conductivity type is implanted onto a silicon carbide substrate through an opening in a mask layer. First and second films made of first and second materials respectively are formed. It is sensed that etching of the first material is performed during anisotropic etching, and then anisotropic etching is stopped. An impurity of a second conductivity type is implanted onto the silicon carbide substrate through the opening narrowed by the first and second films. Thus, the impurity regions can be formed in an accurately self-aligned manner.

Abstract: A method for fabricating a semiconductor device includes forming a structure having first surfaces at a height above a second surface, which is provided between the first surfaces, forming a first silicon layer on the structure, performing a tilt ion implantation process on the first silicon layer to form a crystalline region and an amorphous region, forming a second silicon layer on the amorphous region, removing the second silicon layer and the first silicon layer until a part of the second surface is exposed, thereby forming an etch barrier, and etching using the etch barrier to form an open part that exposes a part of a sidewall of the structure.

Abstract: Techniques are here disclosed for a solar cell pre-processing method and system for annealing and gettering a solar cell semiconductor wafer having an undesirably high dispersion of transition metals, impurities and other defects. The process forms a surface contaminant layer on the solar cell semiconductor (e.g., silicon) wafer. A surface of the semiconductor wafer receives and holds impurities, as does the surface contaminant layer. The lower-quality semiconductor wafer includes dispersed defects that in an annealing process getter from the semiconductor bulk to form impurity cluster toward the surface contaminant layer. The impurity clusters form within the surface contaminant layer while increasing the purity level in wafer regions from which the dispersed defects gettered. Cooling follows annealing for retaining the impurity clusters and, thereby, maintaining the increased purity level of the semiconductor wafer in regions from which the impurities gettered.

Abstract: Disclosed are an SiC semiconductor element and manufacturing method for an SiC semiconductor element in which the interface state density of the interface of the insulating film and the SiC is reduced, and channel mobility is improved. Phosphorus (30) is added to an insulating film (20) formed on an SiC semiconductor (10) substrate in a semiconductor element. The addition of phosphorous to the insulating film makes it possible to significantly reduce the defects (interface state density) in the interface (21) of the insulating film and the SiC, and to dramatically improve the channel mobility when compared with conventional SiC semiconductor elements. The addition of phosphorus to the insulating film is carried out by heat treatment. The use of heat treatment to add phosphorous to the insulating film makes it possible to maintain the reliability of the insulating film, and to avoid variation in channel mobility and threshold voltage.

Abstract: A method of manufacturing a MOSFET includes the steps of preparing a substrate with an epitaxial growth layer made of silicon carbide, performing ion implantation into the substrate with the epitaxial growth layer, forming a protective film made of silicon nitride on the substrate with the epitaxial growth layer into which the ion implantation was performed, and heating the substrate with the epitaxial growth layer on which the protective film was formed to a temperature range of 1600° C. or more in an atmosphere containing gas including a nitrogen atom.

Abstract: Exemplary embodiments provide methods of forming semiconductor devices, by which defects formed upon nucleation and coalescence of semiconductor islands can be reduced or eliminated. In one embodiment, an annealing process can be performed prior to coalescence of the semiconductor islands into a continuous semiconductor layer. In another embodiment, high-quality Group III-V materials can be formed on the continuous semiconductor layer.

Abstract: The thickness of drain and source areas may be reduced by a cavity etch used for refilling the cavities with an appropriate semiconductor material, wherein, prior to the epitaxial growth, an implantation process may be performed so as to allow the formation of deep drain and source areas without contributing to unwanted channel doping for a given critical gate height. In other cases, the effective ion blocking length of the gate electrode structure may be enhanced by performing a tilted implantation step for incorporating deep drain and source regions.

Abstract: A method for generating n-type carriers in a semiconductor is disclosed. The method includes supplying a semiconductor having an atomic radius. Implanting an n-type dopant species into the semiconductor, which n-type dopant species has a dopant atomic radius. Implanting a compensating species into the semiconductor, which compensating species has a compensating atomic radius. Selecting the n-type dopant species and the compensating species in such manner that the size of the semiconductor atomic radius is inbetween the dopant atomic radius and the compensating atomic radius. A further method is disclosed for generating n-type carriers in germanium (Ge). The method includes setting a target concentration for the carriers, implanting a dose of an n-type dopant species into the Ge, and selecting the dose to correspond to a fraction of the target carrier concentration. Thermal annealing the Ge in such manner as to activate the n-type dopant species and to repair a least a portion of the implantation damage.

Abstract: A termination configuration of a silicon carbide insulating gate type semiconductor device includes a semiconductor layer of a first conductivity type having a first main face, a gate electrode, and a source interconnection, as well as a circumferential resurf region. The semiconductor layer includes a body region of a second conductivity type, a source region of the first conductivity type, a contact region of the second conductivity type, and a circumferential resurf region of the second conductivity type. A width of a portion of the circumferential resurf region excluding the body region is greater than or equal to ½ the thickness of at least the semiconductor layer. A silicon carbide insulating gate type semiconductor device of high breakdown voltage and high performance can be provided.

Abstract: A single crystal silicon etching method includes providing a single crystal silicon substrate having at least one trench therein. The single crystal silicon substrate is exposed to an anisotropic etchant that undercuts the single crystal silicon. By controlling the length of the etch, single crystal silicon islands or smooth vertical walls in the single crystal silicon may be created.

Abstract: The mechanisms of forming SiC crystalline regions on Si substrate described above enable formation and integration of GaN-based devices and Si-based devices on a same substrate. The SiC crystalline regions are formed by implanting carbon into regions of Si substrate and then annealing the substrate. An implant-stop layer is used to cover the Si device regions during formation of the SiC crystalline regions.

Abstract: A semiconductor device exhibiting enhanced carrier mobility within a channel region of the semiconductor device is disclosed. The semiconductor device includes a gate stack having first and second sidewall spacers, where the gate stack is implemented above the channel region of the semiconductor device. The semiconductor device further includes first and second trenches formed adjacent to the gate stack, where the first and second trenches are conically shaped to be wider at a top portion of each trench as compared to a width of each trench below the top portion of each trench. The semiconductor device further includes strained silicon alloy formed within the first and second trenches, where a stress force exerted on the channel region of the semiconductor device is maximized at a surface of the semiconductor device below the gate stack.

Abstract: An object is to provide a method for manufacturing a silicon carbide semiconductor device in which a time required for removing a sacrificial oxide film can be shortened and damage to a surface of the silicon carbide layer can be reduced. The method for manufacturing a silicon carbide semiconductor device includes: (a) performing ion implantation to a silicon carbide layer; (b) performing activation annealing to the ion-implanted silicon carbide layer 2; (c) removing a surface layer of the silicon carbide layer 2, to which the activation annealing has been performed, by dry etching; (d) forming a sacrificial oxide film on a surface layer of the silicon carbide layer, to which the dry etching has been performed, by performing sacrificial oxidation thereto; and (e) removing the sacrificial oxide film by wet etching.