Abstract: A semiconductor process includes the following steps. A gate structure is formed on a substrate. A main spacer is formed on the substrate beside the gate structure. A source/drain is formed in the substrate beside the main spacer. After the source/drain is formed, an epitaxial structure is formed in the substrate beside the main spacer. A gate structure may be respectively formed in a first area and a second area of a substrate. A main spacer is formed on the substrate respectively beside the two gate structures. A source/drain is formed in the substrate respectively beside the two spacers. After the two source/drains are formed, an epitaxial structure is formed in the substrate respectively beside the main spacers.

Abstract: A method for forming a transistor includes providing a patterned gate stack disposed on a III-V substrate and having sidewall spacers formed on sides of the patterned gate stack, the III-V substrate including source/drain regions adjacent to the sidewall spacers and field oxide regions formed adjacent to the source/drain regions. The method includes growing raised source/drain regions on the source/drain regions, the grown raised source/drain regions including III-V semiconductor material, and growing metal contacts on the grown raised source/drain regions. Another method for forming a transistor includes providing a patterned gate stack disposed on a III-V substrate and having sidewall spacers formed on sides of the patterned gate stack, the III-V substrate including source/drain regions adjacent to the sidewall spacers and field oxide regions formed adjacent to the source/drain regions. The method includes growing metal contacts on the source/drain regions.

Abstract: A semiconductor device having dislocations and a method of fabricating the semiconductor device is disclosed. The exemplary semiconductor device and method for fabricating the semiconductor device enhance carrier mobility. The method includes providing a substrate having an isolation feature therein and two gate stacks overlying the substrate, wherein one of the gate stacks is atop the isolation feature. The method further includes performing a pre-amorphous implantation process on the substrate. The method further includes forming a stress film over the substrate. The method also includes performing an annealing process on the substrate and the stress film.

Abstract: A semiconductor structure and a method for forming the same are provided. The semiconductor structure includes a substrate; a plurality of convex structures formed on the substrate, in which every two adjacent convex structures are separated by a cavity; a plurality of floated films, in which each floated film is formed between the every two adjacent convex structures and connected with tops of the every two adjacent convex structures, the floated films are partitioned into a plurality of sets, a channel layer is formed on a convex structure between the floated films in each set, a source region and a drain region are formed on two sides of the channel layer respectively, and an isolation portion is set between two adjacent sets of floated films; and a gate stack formed on each channel layer.

Abstract: Recesses are formed in a pMOS region 2, and a SiGe layer is then formed so as to cover a bottom surface and a side surface of each of the recesses. Next, a SiGe layer containing Ge at a lower content than that in the SiGe layer is formed on each of the SiGe layers.

Abstract: Disclosed are a method of manufacturing a field-effect transistor. The disclosed method includes: providing a semiconductor substrate; forming a source ohmic metal layer on one side of the semiconductor substrate; forming a drain ohmic metal layer on another side of the semiconductor substrate; forming a gate electrode between the source ohmic metal layer and the drain ohmic metal layer, on an upper portion of the semiconductor substrate; forming an insulating film on the semiconductor substrate's upper portion including the source ohmic metal layer, the drain ohmic metal layer and the gate electrode; and forming a plurality of field electrodes on an upper portion of the insulating film, wherein the insulating film below the respective field electrodes has different thicknesses.

Abstract: A method of manufacturing a semiconductor device may include forming a first n? type epitaxial layer by performing a first epitaxial growth on a first surface of an n+ type silicon carbide substrate, forming a photosensitive layer pattern on the first n? type epitaxial layer, etching the first n? type epitaxial layer by using the photosensitive layer pattern as a mask to form a first trench, forming a buffer layer on the first n? type epitaxial layer after the photosensitive layer pattern may be removed, etching the buffer layer to form a trench passivation layer in the first trench, forming an n? type epitaxial layer by performing a second epitaxial growth on the first n? type epitaxial layer, and forming a p type epitaxial layer by performing a third epitaxial growth on the n? type epitaxial layer other than the portion on which the trench passivation layer may be formed.

Abstract: The benefits of strained semiconductors are combined with silicon-on-insulator approaches to substrate and device fabrication.

Abstract: An embodiment of the invention reduces the external resistance of a transistor by utilizing a silicon germanium alloy for the source and drain regions and a nickel silicon germanium self-aligned silicide (i.e., salicide) layer to form the contact surface of the source and drain regions. The interface of the silicon germanium and the nickel silicon germanium silicide has a lower specific contact resistivity based on a decreased metal-semiconductor work function between the silicon germanium and the silicide and the increased carrier mobility in silicon germanium versus silicon. The silicon germanium may be doped to further tune its electrical properties. A reduction of the external resistance of a transistor equates to increased transistor performance both in switching speed and power consumption.

Abstract: A field effect transistor structure that uses thin semiconductor on insulator channel to control the electrostatic integrity of the device. Embedded stressors are epitaxially grown in the source/drain area from a template in the silicon substrate through an opening made in the buried oxide in the source/drain region. In addition, a dielectric layer is formed between the embedded stressor and the semiconductor region under the buried oxide layer, which is located directly beneath the channel to suppress junction capacitance and leakage.

Abstract: Methods for forming a buried-channel field-effect transistor include doping source and drain regions on a substrate with a dopant having a first type; forming a doped shielding layer on the substrate in a channel region having a second doping type opposite the first type to displace a conducting channel away from a gate-interface region; forming a gate dielectric over the doped shielding layer; and forming a gate on the gate dielectric.

Abstract: A method of fabricating a semiconductor device for improving the performance of “?” shaped embedded source/drain regions is disclosed. A “U” shaped recess is formed in a Si substrate. The recess is treated with a surfactant, the amount of surfactant adsorbed on the recess sidewalls being greater than that on the recess bottom. An oxide is formed on the bottom. The presence of surfactant on the sidewalls, prevents oxide from forming thereon. The surfactant on the sidewalls is then removed and an orientation selective wet etching process is performed on the sidewalls. The oxide protects the Si at the bottom is from being etched.

Abstract: Two layers of protection films are formed such that a sheet resistance at a portion directly below the protection film is higher than that at a portion directly below the protection film. The protection films are formed, for example, of SiN film, as insulating films. The protection film is formed to be higher, for instance, in hydrogen concentration than the protection film so that the protection film is higher in refractive index the protection film. The protection film is formed to cover a gate electrode and extend to the vicinity of the gate electrode on an electron supplying layer. The protection film is formed on the entire surface to cover the protection film. According to this configuration, the gate leakage is significantly reduced by a relatively simple configuration to realize a highly-reliable compound semiconductor device achieving high voltage operation, high withstand voltage, and high output.

Abstract: A semiconductor device including a gate electrode disposed on a semiconductor substrate and source/drain regions disposed at both sides of the gate electrode, the source/drain regions being formed by implanting impurities. The source/drain regions include an epitaxial layer formed by epitaxially growing a semiconductor material having a different lattice constant from that of the semiconductor substrate in a recessed position at a side of the gate electrode, and a diffusion layer disposed in a surface layer of the semiconductor substrate.

Abstract: A method of forming transistors with close proximity stressors to channel regions of the transistors is provided. The method includes forming a first transistor, in a first region of a substrate, having a gate stack on top of the first region of the substrate and a set of spacers adjacent to sidewalls of the gate stack, the first region including a source and drain region of the first transistor; forming a second transistor, in a second region of the substrate, having a gate stack on top of the second region of the substrate and a set of spacers adjacent to sidewalls of the gate stack, the second region including a source and drain region of the second transistor; covering the first transistor with a photo-resist mask without covering the second transistor; creating recesses in the source and drain regions of the second transistor; and forming stressors in the recesses.

Abstract: In a method of manufacturing a semiconductor device, a source/drain feature is formed over a substrate. A Si-containing layer is formed over the source/drain feature. A metal layer is formed over the Si-containing layer. A metal silicide layer is formed from the metal layer and Si in the Si-containing layer.

Abstract: Methods for fabricating a field effect transistor having at least one structure configured to redistribute and/or reduce an electric field from gate finger ends are disclosed. The methods provide field effect transistors that each include a substrate, an active region disposed on the substrate, at least one source finger in contact with the active region, at least one drain finger in contact with the active region, and at least one gate finger in rectifying contact with the active region. One embodiment has at least one end of the at least one gate finger extending outside of the active region. At least one method includes etching at least one gate channel into the passivation layer with a predetermined slope that reduces electric fields at a gate edge. Other methods include steps for fabricating a sloped gate foot, a round end, and/or a chamfered end to further improve high voltage operation.

Abstract: Transistor structures having channel regions comprising alternating layers of compressively and tensilely strained epitaxial materials are provided. The alternating epitaxial layers can form channel regions in single and multigate transistor structures. In alternate embodiments, one of the two alternating layers is selectively etched away to form nanoribbons or nanowires of the remaining material. The resulting strained nanoribbons or nanowires form the channel regions of transistor structures. Also provided are computing devices comprising transistors comprising channel regions comprised of alternating compressively and tensilely strained epitaxial layers and computing devices comprising transistors comprising channel regions comprised of strained nanoribbons or nanowires.

Abstract: A low leakage current switch device (110) is provided which includes a GaN-on-Si substrate (11-13) covered by a passivation surface layer (43) in which a T-gate electrode with sidewall extensions (48) is formed and coated with a conformal passivation layer (49) so that the T-gate electrode sidewall extensions are spaced apart from the underlying passivation surface layer (43) by the conformal passivation layer (49).

Abstract: A semiconductor device includes, a gate insulating film, a gate electrode, a source/drain region, and a Si mixed crystal layer in the source/drain region. The Si mixed crystal layer includes a first Si mixed crystal layer that includes impurities with a first concentration, a second Si mixed crystal layer formed over the first Si mixed crystal layer and that includes the impurities with a second concentration higher than the first concentration, and a third Si mixed crystal layer formed over the second Si mixed crystal layer and that includes the impurities with a third concentration lower than the second concentration.

Abstract: A method for preparing a Group 1a-1b-3a-6a material using a selenium/Group 1b ink comprising, as initial components: a selenium component comprising selenium, an organic chalcogenide component having a formula selected from RZ—Z?R? and R2—SH, a Group 1b component and a liquid carrier; wherein Z and Z? are each independently selected from sulfur, selenium and tellurium; wherein R is selected from H, C1-20 alkyl group, a C6-20 aryl group, a C1-20 alkylhydroxy group, an arylether group and an alkylether group; wherein R? and R2 are selected from a C1-20 alkyl group, a C6-20 aryl group, a C1-20 alkylhydroxy group, an arylether group and an alkylether group; and wherein the selenium/Group 1b ink is a stable dispersion.

Abstract: The present invention relates to a transistor and the method for forming the same. The transistor of the present invention comprises a semiconductor substrate; a gate dielectric layer formed on the semiconductor substrate; a gate formed on the gate dielectric layer; a channel region under the gate dielectric layer; and a source region and a drain region located in the semiconductor substrate and on respective sides of the channel region, wherein at least one of the source and drain regions comprises a set of dislocations that are adjacent to the channel region and arranged in the direction perpendicular to a top surface of the semiconductor substrate, and the set of dislocations comprises at least two dislocations.

Abstract: A semiconductor structure includes agate structure, an epitaxial layer and a carbon-containing silicon germanium cap layer. The gate structure is located on a substrate. The epitaxial layer is located in the substrate beside the gate structure. The carbon-containing silicon germanium cap layer is located on the epitaxial layer. Otherwise, semiconductor processes for forming said semiconductor structure are also provided.

Abstract: Techniques are disclosed for forming column IV transistor devices having source/drain regions with high concentrations of germanium, and exhibit reduced parasitic resistance relative to conventional devices. In some example embodiments, the source/drain regions each includes a thin p-type silicon or germanium or SiGe deposition with the remainder of the source/drain material deposition being p-type germanium or a germanium alloy (e.g., germanium:tin or other suitable strain inducer, and having a germanium content of at least 80 atomic % and 20 atomic % or less other components). In some cases, evidence of strain relaxation may be observed in the germanium rich cap layer, including misfit dislocations and/or threading dislocations and/or twins. Numerous transistor configurations can be used, including both planar and non-planar transistor structures (e.g., FinFETs and nanowire transistors), as well as strained and unstrained channel structures.

Abstract: An embodiment of a method of manufacturing a compound semiconductor device includes: forming an initial layer over a substrate; forming a buffer layer over the initial layer; forming an electron transport layer and an electron supply layer over the buffer layer; and forming a gate electrode, a source electrode and a gate electrode over the electron supply layer. The forming an initial layer includes: forming a first compound semiconductor film with a flow rate ratio being a first value, the flow rate ratio being a ratio of a flow rate of a V-group element source gas to a flow rate of a III-group element source gas; and forming a second compound semiconductor film with the flow rate ratio being a second value different from the first value over the first compound semiconductor film. The method further includes forming an Fe-doped region between the buffer layer and the electron transport layer.

Abstract: A III-nitride switch includes a recessed gate contact to produce a nominally off, or an enhancement mode, device. By providing a recessed gate contact, a conduction channel formed at the interface of two III-nitride materials is interrupted when the gate electrode is inactive to prevent current flow in the device. The gate electrode can be a schottky contact or an insulated metal contact. Two gate electrodes can be provided to form a bi-directional switch with nominally off characteristics. The recesses formed with the gate electrode can have sloped sides. The gate electrodes can be formed in a number of geometries in conjunction with current carrying electrodes of the device.

Abstract: In one aspect, a method of fabricating a metal silicide includes the following steps. A semiconductor material selected from the group consisting of silicon and silicon germanium is provided. A metal(s) is deposited on the semiconductor material. A first anneal is performed at a temperature and for a duration sufficient to react the metal(s) with the semiconductor material to form an amorphous layer including an alloy formed from the metal(s) and the semiconductor material, wherein the temperature at which the first anneal is performed is below a temperature at which a crystalline phase of the alloy is formed. An etch is used to selectively remove unreacted portions of the metal(s). A second anneal is performed at a temperature and for a duration sufficient to crystallize the alloy thus forming the metal silicide. A device contact and a method of fabricating a FET device are also provided.

Abstract: A method for fabricating a semiconductor device, the method includes forming a gate stack over a major surface of a substrate. The method further includes recessing the substrate to form source and drain recess cavities adjacent to the gate stack in the substrate. The method further includes selectively growing a strained material in the source and drain recess cavities in the substrate using an LPCVD process, wherein the LPCVD process is performed at a temperature of about 660 to 700° C. and under a pressure of about 13 to 50 Torr, using SiH2Cl2, HCl, GeH4, B2H6, and H2 as reaction gases.

Abstract: A semiconductor structure and a method for forming the same are provided. The semiconductor structure comprises: a semiconductor substrate; an active region formed in the semiconductor substrate, in which the active region comprises: a channel region, and a source region and a drain region formed on both sides of the channel region respectively; and a first isolation trench formed in the semiconductor substrate and on both sides of the active region, in which a first rare earth oxide layer is formed in each first isolation trench to produce a stress in the channel region in a channel length direction.

Abstract: Methods for fabricating integrated circuits are provided. In an embodiment, a method for fabricating an integrated circuit includes forming a gate stack on a semiconductor substrate. In the method, a first halo implantation is performed on the semiconductor substrate with a first dose of dopant ions to form first halo regions therein. A second halo spacer is formed around the gate stack. Then a second halo implantation is performed on the semiconductor substrate with a second dose of dopant ions to form second halo regions therein.

Abstract: A method of fabricating a semiconductor device may form a nitride semiconductor layer on a substrate, form a first insulator layer on the nitride semiconductor layer by steam oxidation of ALD, form a second insulator layer on the first insulator layer by oxygen plasma oxidation of ALD, form a gate electrode on the second insulator layer, and form a source and drain electrodes on the nitride semiconductor layer. The nitride semiconductor layer may include a first semiconductor layer on the substrate, and a second semiconductor layer on the first semiconductor layer.

Abstract: Semiconductor devices and methods of manufacture thereof are disclosed. In one embodiment, a method of manufacturing a semiconductor device includes forming a channel region in a workpiece, and forming a source or drain region proximate the channel region. The source or drain region includes a contact resistance-lowering material layer comprising SiP, SiAs, or a silicide. The source or drain region also includes a channel-stressing material layer comprising SiCP or SiCAs.

Abstract: According to one embodiment, an SiC semiconductor device comprises a p-type 4H—SiC region formed on at least part of a surface portion of an SiC substrate, a defect reduction layer formed on a surface portion of the 4H—SiC region, a gate insulating film formed on the defect reduction layer, and a gate electrode formed on the gate insulating film. The defect reduction layer has the C defect density that is defined as follows and is set to Cdef<1015 cm?3 by introduction of carbon.

Abstract: A device includes a semiconductor substrate, a gate stack over the semiconductor substrate, and a stressor region having at least a portion in the semiconductor substrate and adjacent to the gate stack. The stressor region includes a first stressor region having a first p-type impurity concentration, a second stressor region over the first stressor region, wherein the second stressor region has a second p-type impurity concentration, and a third stressor region over the second stressor region. The third stressor region has a third p-type impurity concentration. The second p-type impurity concentration is lower than the first and the third p-type impurity concentrations.

Abstract: According to one embodiment, a semiconductor device includes a first, a second, a third, a fourth, and a fifth semiconductor region, an insulating film, a control electrode, and a first and a second electrode. The first, the second, the third, the fourth and the fifth semiconductor region include silicon carbide. The first semiconductor region has a first impurity concentration, and has a first portion. The second semiconductor region is provided on the first semiconductor region. The third semiconductor region is provided on the second semiconductor region. The fourth semiconductor region is provided between the first portion and the second semiconductor region. The fourth semiconductor region is provided between the first portion and the third semiconductor region. The fifth semiconductor region includes a first region provided between the first portion and the second semiconductor region, and has a second impurity concentration higher than the first impurity concentration.

Abstract: A nickelide material with reduced resistivity is provided as source/drain contact surfaces in both NMOS and PMOS technology. The nickelide material layer may be a ternary material such as NiInAs, and may be formed from a binary material previously formed in the source/drain regions. The binary material may be the channel material or it may be an epitaxial layer formed over the channel material. The same ternary nickelide material may be used as the source/drain contact surface in both NMOS and PMOS transistors. Various binary or ternary channel materials may be used for the NMOS transistors and for the PMOS transistors.

Abstract: A method to form a strain-inducing semiconductor region is described. In one embodiment, formation of a strain-inducing semiconductor region laterally adjacent to a crystalline substrate results in a uniaxial strain imparted to the crystalline substrate, providing a strained crystalline substrate. In another embodiment, a semiconductor region with a crystalline lattice of one or more species of charge-neutral lattice-forming atoms imparts a strain to a crystalline substrate, wherein the lattice constant of the semiconductor region is different from that of the crystalline substrate, and wherein all species of charge-neutral lattice-forming atoms of the semiconductor region are contained in the crystalline substrate.

Abstract: A larger substrate can be used, and a transistor having a desirably high field-effect mobility can be manufactured through formation of an oxide semiconductor layer having a high degree of crystallinity, whereby a large-sized display device, a high-performance semiconductor device, or the like can be put into practical use. A first multi-component oxide semiconductor layer is formed over a substrate and a single-component oxide semiconductor layer is formed thereover; then, crystal growth is carried out from a surface to an inside by performing heat treatment at 500° C. to 1000° C. inclusive, preferably 550° C. to 750° C. inclusive so that a first multi-component oxide semiconductor layer including single crystal regions and a single-component oxide semiconductor layer including single crystal regions are formed; and a second multi-component oxide semiconductor layer including single crystal regions is stacked over the single-component oxide semiconductor layer including single crystal regions.

Abstract: A replacement gate process for fabricating a semiconductor device with metal gates includes forming a dummy gate stack, patterning dummy gates, doping source and drain regions for the gates, and forming an inter-level dielectric layer that overlays the source and drain regions. The sacrificial layer of the dummy gates is removed to form trenches using a three stage process. The first stage begins the trenches, whereby trenches entrance corners are exposed. The second stage is an etch that rounds the corners. The third stage is a main etch for the sacrificial layer, which is typically polysilicon. The corner rounding of the second stage improves the performance of the third stage and results in a better metal back fill including a reduction in pit defects. The process improves overall device yield in comparison to an otherwise equivalent process that omits the corner rounding step.

Abstract: A device includes a semiconductor substrate, a first Metal-Oxide-Semiconductor (MOS) device, and a second MOS device of a same conductivity as the first MOS device. The first MOS device includes a first gate stack over the semiconductor substrate, and a first stressor adjacent to the first gate stack and extending into the semiconductor substrate. The first stressor and the first gate stack have a first distance. The second MOS device includes a second gate stack over the semiconductor substrate, and a second stressor adjacent to the second gate stack and extending into the semiconductor substrate. The second stressor and the second gate stack have a second distance greater than the first distance.

Abstract: A method to reduce (avoid) Fermi Level Pinning (FLP) in high mobility semiconductor compound channel such as Ge and III-V compounds (e.g. GaAs or InGaAs) in a Metal Oxide Semiconductor (MOS) device. The method is using atomic hydrogen which passivates the interface of the high mobility semiconductor compound with the gate dielectric and further repairs defects. The methods further improve the MOS device characteristics such that a MOS device with a quantum well is created.

Abstract: A CMOS device includes a PMOS transistor with a first quantum well structure and an NMOS device with a second quantum well structure. The PMOS and NMOS transistors are formed on a substrate.

Abstract: A semiconductor device includes a first semiconductor layer, a second semiconductor layer, a two-dimensional carrier gas layer, a first main electrode, a second main electrode, a first gate electrode, and a second gate electrode. The first gate electrode is provided between a part of the first main electrode and a part of the second main electrode opposite to the part of the first main electrode. The second gate electrode is provided between another part of the first main electrode and another part of the second main electrode opposite to the another part of the first main electrode with a separation region interposed between the first gate electrode and the second gate electrode. The second gate electrode is controlled independently of the first gate electrode.

Abstract: There are disclosed herein various implementations of a transistor having a segmented gate region. Such a transistor may include at least one segmentation dielectric segment and two or more gate dielectric segments. The segmentation dielectric segment or segments are thicker than the gate dielectric segments, and is/are situated between the gate dielectric segments. The segmentation dielectric segment or segments cause an increase in the effective gate length so as to improve resistance to punch-through breakdown between a drain electrode and a source electrode of the transistor when the transistor is off.

Abstract: A method of forming a fin field effect transistor (finFET) device includes forming a silicon fin on a substrate; forming an inner spacer adjacent to a first portion of the silicon fin; forming silicon germanium regions adjacent to a second portion of the silicon fin and the inner spacer; and oxidizing the silicon germanium regions, such that the second portion of the silicon fin that is located adjacent to the silicon germanium regions is converted to a silicon germanium channel region during oxidizing of the silicon germanium regions, and such that the first portion of the silicon fin is protected by the inner spacer during oxidation of the silicon germanium regions, wherein the first portion of the silicon fin comprises a silicon buffer region located between the silicon germanium channel region and a source/drain region of the finFET device.

Abstract: A method for fabricating a transistor with uniaxial stress channels includes depositing an insulating layer onto a substrate, defining bars within the insulating layer, recessing a channel into the substrate, growing a first semiconducting material in the channel, defining a gate stack over the bars and semiconducting material, defining source and drain recesses and embedding a second semiconducting material into the source and drain recesses.

Abstract: A method includes: etching a silicon substrate except for a silicon substrate portion on which a channel region is to be formed to form first and second trenches respectively at a first side and a second side of the silicon substrate portion; filling the first and second trenches by epitaxially growing a semiconductor layer having etching selectivity against silicon and further a silicon layer; removing the semiconductor layer selectivity by a selective etching process to form voids underneath the silicon layer respectively at the first side and the second side of the substrate portion; burying the voids at least partially with a buried insulation film; forming a gate insulation film and a gate electrode on the silicon substrate portion; and forming a source region in the silicon layer at the first side of the silicon substrate portion and a drain region at the second side of the silicon substrate portion.

Abstract: A field effect transistor and method of fabrication are provided. The field effect transistor comprises a plurality of elongated uniaxially-strained SiGe regions disposed on a silicon substrate, oriented such that they are in parallel to the direction of flow of electrical carriers in the channel. The elongated uniaxially-strained SiGe regions are oriented perpendicular to, and traverse through the transistor gate.

Abstract: A first layer constituting a first surface of a silicon carbide layer and of a first conductivity type is prepared. An internal trench is formed at a face opposite to the first surface of the first layer. Impurities are implanted such that the conductivity type of the first layer is inverted on the sidewall of the internal trench. By the implantation of impurities, there are formed from the first layer an implantation region located on the sidewall of the internal trench and of a second conductivity type, and a non-implantation region of the first conductivity type. A second layer of the first conductivity type is formed, filling the internal trench, and constituting the first region together with the non-implantation region.

Abstract: A semiconductor structure and a method of fabricating the same comprising the steps of providing a substrate, forming at least one fin structure on said substrate, forming a gate covering said fin structure, forming a plurality of epitaxial structures covering said fin structures, performing a gate pullback process to reduce the critical dimension (CD) of said gate and separate said gate and said epitaxial structures, forming lightly doped drains (LDD) in said fin structures, and forming a spacer on said gate and said fin structures.