Abstract: A FinFET body contact structure and a method for creating the FinFET body contact structure are disclosed. The body contact structure comprises a wide fin portion of a semiconductor fin, the wide fin portion having a polysilicon polygon shape formed on a top surface of the wide fin portion. The polysilicon polygon shape has a center area having no polysilicon. FinFETs are formed on two vertical surfaces of the wide fin portion and gates of the FinFETs are coupled to the polysilicon polygon shape. Top surfaces of the wide fin portion and the polysilicon polygon shape are silicided. Silicide bridging is prevented by sidewall spacers. All convex angles on the polysilicon polygon shape are obtuse enough to prevent creation of bridging vertices. The center area is doped of an opposite type from a source and a drain of an associated FinFET.

Abstract: The present invention provides a FinFET transistor arrangement produced using a method with the steps: providing a substrate (106, 108); forming an active region (1) on the substrate a fin-like channel region (113b?; 113b?). Formation of the fin-like channel region (113b?; 113b?) has the following steps: forming a hard mask (S1-S4) on the active region (1); anisotropic etching of the active region (1) using the hard mask (S1-S4) forming STI trenches (G1-G5) having an STI oxide filling (9); polishing-back of the STI oxide filling (9); etching-back of the polished-back STI oxide filling (9); selective removal of components of the hard mask forming a modified hard mask (S1?-S4?); anisotropic etching of the active region (1) using the modified hard mask (S1?-S4?) forming widened STI trenches (G1?-G5?), the fin-like channel regions (113b?; 113b?) of the active region (1) remaining for each individual FinFET transistor.

Abstract: A method for manufacturing a fin transistor includes forming a trench by etching a semiconductor substrate. A flowable insulation layer is filled in the trench to form a field insulation layer defining an active region. The portion of the flowable insulation layer coming into contact with a gate forming region is etched so as to protrude the gate forming region in the active region. A protective layer over the semiconductor substrate is formed to fill the portion of the etched flowable insulation layer. The portion of the protective layer formed over the active region is removed to expose the active region of the semiconductor substrate. The exposed active region of the semiconductor substrate is cleaned. The protective layer remaining on the portion of the etched flowable insulation layer is removed. Gates are formed over the protruded gate forming regions in the active region.

Abstract: Non-planar SOI devices that include an “area-efficient” body tie are disclosed. The device includes a bulk substrate, an insulator layer formed on a surface of the bulk substrate, and a silicon body formed on a surface of the insulator layer. The silicon body preferably includes (i) a non-planar channel connecting a source region and a drain region, and (ii) a body tie that is adjacent to the channel and couples the channel to a voltage potential. The device further includes a gate dielectric formed on the channel and a gate material formed on the gate dielectric.

Abstract: A thin film transistor substrate according to one or more embodiments of the present invention includes a gate line formed on a substrate, a data line that is insulated from and intersects the gate line, a thin film transistor connected to the gate line and the data line, a barrier rub formed on the thin film transistor and partitioning a plurality of first openings, a reflecting electrode formed in each of the first openings, and a pixel electrode formed on the reflecting electrode and that is electrically connected to the thin film transistor.

Abstract: A field effect device is disclosed which has a body formed of a crystalline semiconductor material and has at least one vertically oriented section and at least one horizontally oriented section. The device is produced in SOI technology by fabricating first a formation of the device in masking insulators, and then transferring this formation through several etching steps into the SOI layer. The segmented field effect device combines FinFET, or fully depleted silicon-on-insulator FETs, type devices with fully depleted planar devices. This combination allows device width control with FinFET type devices. The segmented field effect device gives high current drive for a given layout area. The segmented field effect devices allow for the fabrication of high performance processors.

Abstract: Provided is an image display device comprising, on a TFT substrate: a plurality of gate lines and a plurality of drain lines which intersect with each other; a pixel TFT provided within a pixel which is enclosed by a pair of adjacent gate lines and a pair of adjacent drain lines; a gate driver TFT which is connected to one of the plurality of gate lines to drive the one of the plurality of gate lines, wherein the pixel TFT and the gate driver TFT each include an amorphous semiconductor film as a channel, wherein the pixel TFT has a bottom gate structure, wherein the gate driver TFT has a dual gate structure, and wherein a mobility on a top surface side of the semiconductor film of the gate driver TFT is higher than a mobility on a top surface side of the semiconductor film of the pixel TFT.

Abstract: A semiconductor device includes a first insulator formed at a part under a semiconductor layer, a second insulator formed under the semiconductor layer in an arranged manner avoiding the first insulator and having a relative dielectric constant different from that of the first insulator, a backgate electrode formed under the first and second insulators, a gate electrode formed on the semiconductor layer, and a source layer and a drain layer formed in the semiconductor layer to be respectively arranged on opposite lateral sides of the gate electrode.

Abstract: A method for forming a gate electrode for a multiple gate transistor provides a doped, planarized gate electrode material which may be patterned using conventional methods to produce a gate electrode that straddles the active area of the multiple gate transistor and has a constant transistor gate length. The method includes forming a layer of gate electrode material having a non-planar top surface, over a semiconductor fin. The method further includes planarizing and doping the gate electrode material, without doping the source/drain active areas, then patterning the gate electrode material. Planarization of the gate electrode material may take place prior to the introduction and activation of dopant impurities or it may follow the introduction arid activation of dopant impurities. After the gate electrode is patterned, dopant impurities are selectively introduced to the semiconductor fin to form source/drain regions.

Abstract: The present invention provides a semiconductor device includes a substrate including a semiconducting region and isolation regions, a gate structure including a high-k gate dielectric layer atop the semiconducting region of the substrate and a metal gate conductor layer atop the high-k gate dielectric; protective nitride spacers enclosing the high-k gate dielectric layer between the metal gate conductor layer and the semiconducting region of the substrate, the protective nitride spacers separating the isolation regions from the high-k dielectric; and a polysilicon gate conductor overlying the metal gate conductor layer and enclosing the protective nitride spacers between at least the high-k dielectric layer, the semiconducting region, and a portion of the polysilicon gate conductor.

Abstract: A bottom-contacted top gate (TG) thin film transistor (TFT) with independent field control for off-current suppression is provided, along with an associated fabrication method. The method provides a substrate, and forms source and drain regions overlying the substrate, each having a channel interface top surface. A channel is interposed between the source and drain, with source and drain contact regions immediately overlying the source/drain (S/D) interface top surfaces, respectively. A first dielectric layer is formed overlying the source, drain, and channel. A first gate is formed overlying the first dielectric, having a drain sidewall located between the contact regions. A second dielectric layer is formed overlying the first gate and first dielectric. A second gate overlies the second dielectric, located over the drain contact region.

Abstract: A dual gate layout of a thin film transistor of liquid crystal display to alleviate dark current leakage is disclosed. The layout comprises (1) a polysilicon on a substrate having a L-shaped or a snake shaped from top-view, which has a heavily doped source region, a first lightly doped region, a first gate channel, a second lightly doped region, a second gate channel, a third lightly doped region and a heavily doped drain region formed in order therein; (2) a gate oxide layer formed on the polysilicon layer and the substrate, (3) a gate metal layer then formed on the gate oxide layer having a scanning line and an extension portion with a L-shaped or an I-shaped. The gate metal intersects with the polysilicon layer thereto define the forgoing gate channels. Among of gate channels, at least one is along the signal line, which is connected to the source region through a source contact.

Abstract: A thin-film transistor (TFT) is provided. The TFT includes a gate electrode; a dielectric layer and an active layer which are formed on the gate electrode; and source and drain electrodes which are formed on the active layer, each of the source and drain electrodes including a plurality of protruding portions and an empty space between each protruding portion, wherein the source and drain electrodes are spaced apart from each other and engage with each other, and further wherein the gate and source electrodes overlap each other and the gate and drain electrodes overlap each other.

Abstract: The present invention relates to a method for manufacturing a semiconductor film, including the steps of forming a transparent conductive film, forming a first conductive film over the transparent conductive film, forming a second conductive film over the first conductive film, etching the second conductive film with a gas including chlorine, and etching the first conductive film with a gas including fluorine. During etching of the second conductive film with a gas including chlorine, the transparent conductive film is protected by the first conductive film. During etching of the first conductive film with the gas including fluorine, the transparent conductive film does not react with the gas including fluorine. Therefore, no particle is formed.

Abstract: The present invention provides a method of forming a transistor. The method includes forming a first layer of a first semiconductor material above an insulation layer. The first semiconductor material is selected to provide high mobility to a first carrier type. The method also includes forming a second layer of a second semiconductor material above the first layer of semiconductor material. The second semiconductor material is selected to provide high mobility to a second carrier type opposite the first carrier type. The method further includes forming a first masking layer adjacent the second layer and etching the second layer through the first masking layer to form at least one feature in the second layer. Each feature in the second layer forms an inverted-T shape with a portion of the second layer.

Abstract: A unit cell of a metal oxide semiconductor (MOS) transistor is provided including an integrated circuit substrate and a MOS transistor on the integrated circuit substrate. The MOS transistor has a source region, a drain region and a gate. The gate is between the source region and the drain region. First and second spaced apart buffer regions are provided beneath the source region and the drain region and between respective ones of the source region and integrated circuit substrate and the drain region and the integrated circuit substrate.

Abstract: A double-gated fin-type field effect transistor (FinFET) structure has electrically isolated gates. In a method for manufacturing the FinFET structure, a fin, having a gate dielectric on each sidewall corresponding to the central channel region, is formed over a buried oxide (BOX) layer on a substrate. Independent first and second gate conductors on either sidewall of the fin are formed and include symmetric multiple layers of conductive material. An insulator is formed above the fin by either oxidizing conductive material deposited on the fin or by removing conductive material deposited on the fin and filling in the resulting space with an insulating material. An insulating layer is deposited over the gate conductors and the insulator. A first gate contact opening is etched in the insulating layer above the first gate. A second gate contact opening is etched in the BOX layer below the second gate.

Abstract: An object of the present invention is to provide a technique for improving characteristics of a TFT and realizing the structure of the TFT optimal for driving conditions of a pixel section and a driving circuit, using a smaller number of photo masks. A semiconductor device has a semiconductor film, a first electrode, and a first insulating film sandwiched between the semiconductor film and the first electrode, and further has a second electrode, and a second insulating film sandwiched between the semiconductor film and the second electrode. The first electrode and the second electrode overlap with each other across a channel-formed region which the semiconductor film has. A constant voltage is applied to the first electrode at any time.

Abstract: A FinFET device comprises a front gate (FG) and a separate back gate (BG) disposed on opposite sides of the fine. The fin structure may act as a floating body of a volatile memory cell. The front and back gates may be doped with the same or opposite polarity, and may be biased oppositely. A plurality of FinFETs may be connected in a memory array with single column erase, or double column erase capability.

Abstract: A semiconductor memory device and methods of manufacturing and operating the same may be provided. The semiconductor memory device may include a substrate, at least a pair of fins protruding from the semiconductor substrate and facing each other with a gap between fins of the pair of fins, an insulating layer formed between the pair of the fins, a storage node formed on the pair of fins and/or a surface of a portion of the insulating layer, and/or a gate electrode formed on the storage node.

Abstract: An integrated circuit and method for manufacturing an integrated circuit are described. In one embodiment, the integrated circuit includes a memory cell that includes a resistivity changing memory element. The resistivity changing memory element is electrically coupled to a select transistor that includes a FinFET including a source, a drain, and a fin structure formed above a surface of a substrate between the source and the drain. The fin structure includes a channel area extending in a direction substantially parallel to the surface of the substrate, and a dielectric layer formed around at least a portion of the channel area such that an effective channel width of the select transistor depends at least in part on a height of the fin structure.

Abstract: The present invention relates to an image sensor applied with a device isolation technique for reducing dark signals and a fabrication method thereof. The image sensor includes: a logic unit; and a light collection unit in which a plurality of photodiodes is formed, wherein the photodiodes are isolated from each other by a field ion-implantation region formed under a surface of a substrate and an insulation layer formed on the surface of the substrate.

Abstract: The present invention provides a semiconductor device capable of being mass-produced and a manufacturing method of the semiconductor device. The present invention also provides a semiconductor device using an extreme thin integrated circuit and a manufacturing method of the semiconductor device. Further, the present invention provides a low power consumption semiconductor device and a manufacturing method of the semiconductor device. According to one aspect of the present invention, a semiconductor device that has a semiconductor nonvolatile memory element transistor over an insulating surface in which a floating gate electrode of the memory transistor is formed by a plurality of conductive particles or semiconductor particles is provided.

Abstract: A silicon (Si)-on-insulator (SOI) high voltage transistor with a body ground is provided with an associated fabrication process. The method provides a SOI substrate with a buried oxide (BOX) layer and a Si top layer having a first thickness and a second thickness, greater than the first thickness. A body ground is formed in the second thickness of Si top layer overlying the BOX layer. A control channel is formed in the first thickness of the Si top layer. A control gate is formed overlying the control channel. An auxiliary channel is formed in the second thickness of Si top layer partially overlying the body ground and extending into the first thickness of the Si top layer. An auxiliary gate is formed overlying the auxiliary channel. A pn junction is formed in the second thickness of Si top layer between the auxiliary channel and the body ground.

Abstract: A thin film transistor, a method for manufacturing the thin film transistor, and an organic electroluminescence display using the thin film transistor are disclosed. The thin film transistor includes a gate electrode, a semiconductor layer that overlaps the gate electrode, a first insulating layer disposed between the semiconductor layer and the gate electrode, and first and second electrodes that use the semiconductor layer as a channel, and are disposed at different layers. The thin film transistor further includes a second insulating layer disposed between the semiconductor layer and one of the first and second electrodes, and a first doping semiconductor layer disposed between the semiconductor layer and the other of the first and second electrodes.

Abstract: Multi-gate MOS transistors and fabrication methods are described, in which the transistor semiconductor body thickness or width is lithography independent, allowing scaled triple and quad-gate devices having semiconductor bodies smaller than a lateral gate length dimension. A form structure is provided over a semiconductor wafer starting structure, and spacers are formed along one or more sidewalls of an opening in the form structure. A semiconductor material is deposited in the opening by epitaxial growth or other deposition process, and the form structure and the spacer are removed. A gate structure is then formed along the top and sides of a central portion of the formed semiconductor body. The spacer may be L-shaped, providing an undercut or recess at the bottom of the semiconductor body sidewall, and the gate may be formed in the undercut area to allow fabrication of more than three gates.

Abstract: A semiconductor circuit arrangement includes at least one first and a second field effect transistor, where the field effect respectively have at least two active regions with, respectively, a source region, a drain region and an intermediate channel region, the surface of the channel regions having a gate formed on it, insulated by a gate dielectric, for actuating the channeel regions. At least one active region of the second field effect transistor is arranged between the at least two active regions of the first field effect transistor, which results in a reduced mismatch between the two transistors, caused by temperature and local distances.

Abstract: A crystalline semiconductor film in which the position and size of a crystal grain is controlled is fabricated, and the crystalline semiconductor film is used for a channel formation region of a TFT, so that a high performance TFT is realized. An island-like semiconductor layer is made to have a temperature distribution, and a region where temperature change is gentle is provided to control the nucleus generation speed and nucleus generation density, so that the crystal grain is enlarged. In a region where an island-like semiconductor layer 1003 overlaps with a base film 1002, a thick portion is formed in the base film 1002. The volume of this portion increases and heat capacity becomes large, so that a cycle of temperature change by irradiation of a pulse laser beam to the island-like semiconductor layer becomes gentle (as compared with other thin portion).

Abstract: A method of producing a backgated FinFET having different dielectric layer thickness on the front and back gate sides includes steps of introducing impurities into at least one side of a fin of a FinFET to enable formation of dielectric layers with different thicknesses. The impurity, which may be introduced by implantation, either enhances or retards dielectric formation.

Abstract: An unstable factor that the orientation of liquid crystal is fixed and left after a drive power source is turned off is reduced, preferable display quality is realized, and long term reliability is improved. After the drive power source is turned off, in order to block an electric field produced by charges left in a first electrode (485), a second electrode 492 is provided to overlap the first electrode. The first electrode is overlapped at 70% or more of its area with the second electrode. In addition, when the first electrode is used as an electrode composing a retaining capacitor 505, the retaining capacitor is overlapped at 90% or more of its area with the second electrode.

Abstract: The invention primarily provides gate electrodes and gate wirings permitting large-sized screens for active matrix-type display devices, wherein, in order to achieve this object, the construction of the invention is a semiconductor device having, on the same substrate, a pixel TFT provided in a display region and a driver circuit TFT provided around the display region, wherein the gate electrodes of the pixel TFT and the driver circuit TFT are formed from a first conductive layer, the gate electrodes are in electrical contact through connectors with gate wirings formed from a second conductive layer, and the connectors are provided outside the channel-forming regions of the pixel TFT and the driver circuit TFT.

Abstract: A double-gate field effect transistor (DGFET) structure and method of forming such a structure in which the parasitic capacitance under the source/drain regions is substantially reduced are provided. In the present invention, self-aligned isolation regions are provided to reduce the parasitic capacitance in the DGFET structure. Additionally, the present invention encapsulates the silicon-containing channel layer to enable the back-gate to be oxidized to a greater extent thereby reducing the parasitic capacitance of the structure even further.

Abstract: A double-gate transistor having front (upper) and back gates that are aligned laterally is provided. The double-gate transistor includes a back gate thermal oxide layer below a device layer; a back gate electrode below a back gate thermal oxide layer; a front gate thermal oxide above the device layer: a front gate electrode layer above the front gate thermal oxide and vertically aligned with the back gate electrode; and a transistor body disposed above the back gate thermal oxide layer, symmetric with the first gate. The back gate electrode has a layer of oxide formed below the transistor body and on either side of a central portion of the back gate electrode, thereby positioning the back gate self-aligned with the front gate. The transistor also includes source and drain electrodes on opposite sides of said transistor body.

Abstract: A method for ion implanting a tip source and drain region and halo region for a tri-gate field-effect transistor is described. A silicon body is implanted, in one embodiment, from six different angles to obtain ideal regions.

Abstract: A double-gate transistor having front (upper) and back gates that are aligned laterally is provided. The double-gate transistor includes a back gate thermal oxide layer below a device layer; a back gate electrode below a back gate thermal oxide layer; a front gate thermal oxide above the device layer; a front gate electrode layer above the front gate thermal oxide and vertically aligned with the back gate electrode; and a transistor body disposed above the back gate thermal oxide layer, symmetric with the first gate. The back gate electrode has a layer of oxide formed below the transistor body and on either side of a central portion of the back gate electrode, thereby positioning the back gate self-aligned with the front gate. The transistor also includes source and drain electrodes on opposite sides of said transistor body.

Abstract: A non-volatile memory device on a substrate layer (2) comprises source and drain regions (3) and a channel region (4). The source and drain regions (3) and the channel region (4) are arranged in a semiconductor layer (20) on the substrate layer (2). The channel region (4) is fin-shaped and extends longitudinally (X) between the source region and the drain region (3). The channel region (4) comprises two fin portions (4a, 4b) and an intra-fin space (10), the fin portions (4a, 4b) extending in the longitudinal direction (X) and being spaced apart, and the intra-fin space (10) being located in between the fin portions (4a, 4b), and a charge storage area (11, 12; 15, 12) is located in the intra-fin space (10) between the fin portions (4a, 4b).

Abstract: Disclosed is a transistor for a memory device realizing both a step-gated asymmetry transistor and a fin transistor in a cell and a method for manufacturing the same. The transistor has an active region protruding from a predetermined region of a substrate and a groove formed in the active region. A field oxide layer is formed on the substrate around the active region in such a manner that it has a surface lower than the upper surface of the active region including the groove. A pair of gates are placed along one and the other ends of groove across the upper surface of the active region while overlapping the stepped portion of the active region. The transistor has the structure of a step-gated asymmetry transistor when seen in a sectional view taken in a first direction, as well as that of a fin transistor when seen in a sectional view taken in a second direction, which is perpendicular to the first direction.

Abstract: A method of driving a parallel-plate variable micro-electromechanical capacitor includes establishing a first charge differential across first and second conductive plates of a variable capacitor in which the first and second conductive plates are separated by a variable gap distance, isolating the first and second plates for a first duration, decreasing the charge differential to a second charge differential which is less than the first charge differential and in which the second charge differential corresponds to a second value of the variable gap distance.

Abstract: A field effect transistor (FET) device structure and method for forming FETs for scaled semiconductor devices. Specifically, FinFET devices are fabricated from silicon-on-insulator (SOI) wafers in a highly uniform and reproducible manner. The method facilitates formation of FinFET devices with improved and reproducible fin height control while providing isolation between source and drain regions of the FinFET device.

Abstract: An integrated electronic circuit with at least at least one passive electronic component and at least one active electronic component. The passive electronic component is formed within an insulating material disposed on a substrate. The active component is formed within a volume of substantially single-crystal semiconductor material disposed on top of the passive component.

Abstract: The invention relates to a semiconductor device (10) having a semiconductor body (2), comprising a field effect transistor, a first gate dielectric (6A) being formed on a first surface at the location of the channel region (5) and on it a first gate electrode (7), a sunken ion implantation (20) being executed from the first side of the semiconductor body (2) through and on both sides of the first gate electrode (7), which implantation results in a change of property of the silicon below the first gate electrode (7) compared to the silicon on both sides of the gate electrode (7) in a section of the channel region (5) remote from the first gate dielectric (6A), and on the second surface of the semiconductor body (2) a cavity (30) being provided therein by means of selective etching while use is made of the change of property of the silicon. A second gate (6B,8) is deposited in the cavity thus formed.

Abstract: A device isolation film and an active region are formed on a semiconductor substrate, using a first mask pattern to expose only a formation region of the device isolation film. Only the device isolation film is selectively etched by using the first mask pattern and a second mask pattern as an etch mask, to form a fin only on a gate formation region, the second mask pattern to expose only a gate electrode formation region. A gate insulation layer is formed on both sidewalls of the fin and a gate electrode covering the first mask pattern and the gate insulation layer is formed. Source and drain regions are formed on the remaining portion of the active region where the gate electrode was not formed. Gate electrode separation becomes adequate and manufacturing costs can be reduced.

Abstract: A semiconductor device may include at least one pair of fins on a semiconductor substrate. A channel region may be formed in each fin. The semiconductor device may further include a gate electrode corresponding to each pair of channel regions, a source contact plug electrically connected to each of at least one source formed on a respective fin concurrently, and a drain contact plug electrically connected to each of at least one drain formed on a respective fin concurrently.

Abstract: A thin film transistor array substrate includes a polysilicon layer having a predetermined pattern shape formed over a substrate, a first gate insulating film provided over the substrate and on the surface of the polysilicon layer and having a same polished surface as the surface of the polysilicon layer and a second gate insulating film formed to cover the polysilicon layer and the first gate insulating film.

Abstract: Disclosed is a transistor for a memory device realizing both a step-gated asymmetry transistor and a fin transistor in a cell and a method for manufacturing the same. The transistor has an active region protruding from a predetermined region of a substrate and a groove formed in the active region. A field oxide layer is formed on the substrate around the active region in such a manner that it has a surface lower than the upper surface of the active region including the groove. A pair of gates are placed along one and the other ends of groove across the upper surface of the active region while overlapping the stepped portion of the active region. The transistor has the structure of a step-gated asymmetry transistor when seen in a sectional view taken in a first direction, as well as that of a fin transistor when seen in a sectional view taken in a second direction, which is perpendicular to the first direction.

Abstract: Embodiments of the invention include apparatuses and methods relating to three dimensional transistors having high-k dielectrics and metal gates with fins protected by a hard mask layer on their top surface. In one embodiment, the hard mask layer includes an oxide.

Abstract: This invention discloses an improved semiconductor power device includes a plurality of power transistor cells wherein each cell further includes a planar gate padded by a gate oxide layer disposed on top of a drift layer constituting an upper layer of a semiconductor substrate wherein the planar gate further constituting a split gate including a gap opened in a gate layer whereby the a total surface area of the gate is reduced. The transistor cell further includes a JFET (junction field effect transistor) diffusion region disposed in the drift layer below the gap of the gate layer wherein the JFET diffusion region having a higher dopant concentration than the drift region for reducing a channel resistance of the semiconductor power device.

Abstract: A fin-type field effect transistor (FinFET) has a fin having a center channel portion, end portions comprising source and drain regions, and channel extensions extending from sidewalls of the channel portion of the fin. The structure also includes a gate insulator covering the channel portion and the channel extensions, and a gate conductor on the gate insulator. The channel extensions increase capacitance of the channel portion of the fin.

Abstract: A method and device providing a strained Si film with reduced defects is provided, where the strained Si film forms a fin vertically oriented on a surface of a non-conductive substrate. The strained Si film or fin may form a semiconductor channel having relatively small dimensions while also having few defects. The strained Si fin is formed by growing Si on the side of a relaxed SiGe block. A dielectric gate, such as, for example, an oxide, a high “k” material, or a combination of the two, may be formed on a surface of the strained Si film. Additionally, without substantially affecting the stress in the strained Si film, the relaxed SiGe block may be removed to allow a second gate oxide to be formed on the surface previously occupied by the relaxed SiGe block.

Abstract: A multi-gate structure is used and a width (d1) of a high concentration impurity region sandwiched by two channel forming regions in a channel length direction is set to be shorter than a width (d2) of low concentration impurity regions in the channel length direction. Thus, a resistance of the entire semiconductor layer of a TFT which is in an on state is reduced to increase an on current. In addition, a carrier life time due to photoexcitation produced in the high concentration impurity region can be shortened to reduce light sensitivity.