Abstract: Radio frequency and microwave devices and methods of use are provided herein. According to some embodiments, the present technology may comprise an ohmic layer for use in a field effect transistor that includes a plurality of strips disposed on a substrate, the plurality of strips comprising alternating source strips and drain strips, with adjacent strips being spaced apart from one another to form a series of channels, a gate finger segment disposed in each of the series of channels, and a plurality of gate finger pads disposed in an alternating pattern around a periphery of the plurality of strips such that each gate finger segment is associated with two gate finger pads.

Abstract: On a p? epitaxial layer, an n-type epitaxial layer and a gate region are formed in this order. A gate electrode is electrically connected to the gate region, and a source electrode and a drain electrode are spaced apart from each other with the gate electrode sandwiched therebetween. A control electrode is used for applying to the p? epitaxial layer a voltage that causes a reverse biased state of the p? epitaxial layer and the n-type epitaxial layer in an OFF operation.

Abstract: Devices and methods for providing JFET transistors with improved operating characteristics are provided. Specifically, one or more embodiments of the present invention relate to JFET transistors with a higher diode turn-on voltage. For example, one or more embodiments include a JFET with a PIN gate stack. One or more embodiments also relate to systems and devices in which the improved JFET may be employed, as well as methods of manufacturing the improved JFET.

Abstract: Radio frequency and microwave devices and methods of use are provided herein. According to some embodiments, the present technology may comprise an ohmic layer for use in a field effect transistor that includes a plurality of strips disposed on a substrate, the plurality of strips comprising alternating source strips and drain strips, with adjacent strips being spaced apart from one another to form a series of channels, a gate finger segment disposed in each of the series of channels, and a plurality of gate finger pads disposed in an alternating pattern around a periphery of the plurality of strips such that each gate finger segment is associated with two gate finger pads.

Abstract: Transistors, methods of manufacturing thereof, and image sensor circuits are disclosed. In one embodiment, a transistor includes a buried channel disposed in a workpiece, a gate dielectric disposed over the buried channel, and a gate layer disposed over the gate dielectric. The gate layer comprises an I shape in a top view of the transistor.

Abstract: A CMOS structure and a method for fabricating the CMOS structure include within a semiconductor substrate a first gate located over a first active region of a first polarity and a second gate located over a second active region of a second polarity different than the first polarity. The first active region and the second active region are separated by an isolation region. The first gate and the second gate are co-linear, with facing endwalls that terminate over the isolation region. The facing endwalls do not have a spacer located or formed adjacent or adjoining thereto, although sidewalls of the first gate and the second gate do. The CMOS structure may be fabricated using a sequential replacement gate method.

Abstract: Structure and methods for a semiconductor transistor design. The transistor structure comprises a field effect transistor having a multi-finger gate and three or more diffusion regions. Each diffusion region is identified as either a source region or a drain region, and each diffusion region is further identified as either an inner diffusion region or an outer diffusion region. Electrical contacts are established in the inner diffusion regions and the outer diffusion regions. There are approximately twice as many contacts in an inner source region as in the outer source region. There are approximately twice as many contacts in an inner drain region as in the outer drain region. The number and locations of contacts in each diffusion region are adjusted to reduce the difference among source node voltages of all fingers and the difference among drain node voltages of all fingers.

Abstract: Representative implementations of devices and techniques provide a reduced charge transistor arrangement. The capacitance and/or charge of a transistor structure may be reduced by minimizing an overlap of a top gate with respect to a drain of the transistor.

Abstract: Embodiments of a Silicon Nitride (SiN) passivation structure for a semiconductor device and methods of fabrication thereof are disclosed. In general, a semiconductor device includes a semiconductor body and a SiN passivation structure over a surface of the semiconductor body. In one embodiment, the SiN passivation structure includes one or more Hydrogen-free SiN layers on, and preferably directly on, the surface of the semiconductor body, a Hydrogen barrier layer on, and preferably directly on, a surface of the one or more Hydrogen-free SiN layers opposite the semiconductor body, and a Chemical Vapor Deposition (CVD) SiN layer on, and preferably directly on, a surface of the Hydrogen barrier layer opposite the one or more Hydrogen-free SiN layers. The Hydrogen barrier layer preferably includes one or more oxide layers of the same or different compositions. Further, in one embodiment, the Hydrogen barrier layer is formed by Atomic Layer Deposition (ALD).

Abstract: A high voltage junction field effect transistor and a manufacturing method thereof are provided. The high voltage junction field effect transistor includes a base, a drain, a source and a P type top layer. The drain and the source are disposed above the base. A channel is formed between the source and the drain. The P type top layer is disposed above the channel.

Abstract: A junction field-effect transistor (JFET) includes a substrate having a first-type semiconductor surface including a topside surface, and a top gate of a second-type formed in the semiconductor surface. A first-type drain and a first-type source are formed on opposing sides of the top gate. A first deep trench isolation region has an inner first trench wall and an outer first trench wall surrounding the top gate, the drain and the source, and extends vertically to a deep trench depth from the topside surface. A second-type sinker formed in semiconductor surface extends laterally outside the outer first trench wall. The sinker extends vertically from the topside surface to a second-type deep portion which is both below the deep trench depth and laterally inside the inner first trench wall to provide a bottom gate.

Abstract: A non-volatile memory is formed on a substrate. The non-volatile memory includes an isolation structure, a floating gate, and a gate dielectric layer. The isolation structure is disposed in the substrate to define an active area. The floating gate is disposed on the substrate and crosses over the active area. The gate dielectric layer is disposed between the floating gate and the substrate. The floating gate includes a first region and a second region. An energy band of the second region is lower than an energy band of the first region, so that charges stored in the floating gate are away from an overlap region of the floating gate and the gate dielectric layer.

Abstract: A semiconductor structure and method for manufacturing the same are provided. The semiconductor structure includes a substrate having a first conductive type; a deep well having a second conductive type formed in the substrate and extending down from a surface of the substrate; a first well having the first conductive type formed in the deep well and extending down from the surface of the substrate; and a second well having the second conductive type formed in the deep well and extending down from the surface of the substrate, and the second well adjacent to the first well. The first well includes a block region and plural finger regions joined to one side of the block region, while the second well includes plural channel regions interlaced with the finger regions to separate the finger regions.

Abstract: According to one embodiment, a junction type field effect transistor includes a first conductive type semiconductor substrate, a first conductive type drift layer, a second conductive type gate region, a first conductive type channel layer, a first conductive type source region, a source electrode, a drain electrode, a second conductive type gate contact layer, and a gate electrode. The drift layer is provided on a first main surface of the semiconductor substrate. The gate region is provided on a surface of the drift layer. The channel layer is provided on the drift layer and the gate region. The source region is provided on a surface of the channel layer to face the gate region, and has an impurity concentration higher than the channel layer. The source electrode is provided on the channel layer with Schottky contact and on the source region with ohmic contact.

Abstract: Junction field-effect transistors, methods for fabricating junction field-effect transistors, and design structures for a junction field-effect transistor. A source and a drain of the junction field-effect transistor are comprised of a semiconductor material grown by selective epitaxy and in direct contact with a top surface of a semiconductor layer. A gate is formed that is aligned with a channel laterally disposed in the semiconductor layer between the source and the drain. The source, the drain, and the semiconductor layer are each comprised of a second semiconductor material having an opposite conductivity type from a first semiconductor material comprising the gate.

Abstract: A semiconductor device and a method for fabricating the same are described. The semiconductor device includes a well of a first conductive type, first doped regions of a second conductive type, gates of the second conductive type, second doped regions of the first conductive type, and isolation structures. The well is disposed in a substrate. The first doped regions are disposed in the well. The first doped regions are arranged in parallel and extend along a first direction. The gates are disposed on the substrate. The gates are arranged in parallel and extend along a second direction different from the first direction. One of the first doped regions is electrically connected to one of the gates. Each of the second doped regions is disposed in the first doped regions between two adjacent gates. Each of the isolation structures is disposed in the substrate between two adjacent first doped regions.

Abstract: A compound semiconductor device includes a compound semiconductor laminated structure, a passivation film formed on the compound semiconductor laminated structure and having a through-hole, and a gate electrode formed on the passivation film so as to plug the through-hole. A grain boundary between different crystalline orientations is formed in the gate electrode, and a starting point of the grain boundary is located apart from the through-hole on a flat surface of the passivation film.

Abstract: A junction field effect transistor comprising: a semiconductor substrate having a first conductivity type; a channel region having a second conductivity type different from the first conductivity type, and being formed in a surface of the semiconductor substrate; a first buried region having the second conductivity type, being formed within the channel region, and having an impurity concentration higher than the channel region; a first gate region having the first conductivity type, and being formed in a surface of the channel region; and first drain/source region and a second drain/source region both having the second conductivity type, which are formed each on an opposite side of the first gate region in the surface of the channel region, in which the first buried region is not formed below the second drain/source region, but is formed below the first drain/source region.

Abstract: A field effect transistor having a drain, a gate and a source, where the drain and source are formed by semiconductor regions of a first type, and in which a further doped region is provided intermediate the gate and the drain. Field gradients around the drain are thereby reduced.

Abstract: A semiconductor device includes: a gate electrode, a source electrode and a drain electrode, all of which are provided on top of a first surface of a substrate, and each of which includes multiple fingers; and an ohmic electrode layer. The semiconductor device includes: a gate terminal electrode connecting the fingers of the gate electrode together; a source terminal electrode connecting the fingers of the source electrode together; a drain terminal electrode connecting the fingers of the drain electrode together; and a gate pad placed on top of the ohmic electrode layer, and connecting the ohmic electrode layer to the gate terminal electrode. The semiconductor device further includes: an n type semiconductor layer formed in the substrate; a p type semiconductor layer formed in the n type semiconductor layer; and a reaction layer formed in the interface between the p type semiconductor layer substrate and the ohmic electrode layer.

Abstract: A FET includes a first and second set of finger arrays that each include a source, gate and drain. A first source pad is electrically coupled to source electrodes in the first set of finger arrays. A second source pad is electrically coupled to the source electrodes in the second set of finger arrays. A common drain pad is electrically coupled to drain electrodes in the first and second set of finger arrays. A first gate pad is electrically coupled to gate electrodes in the first set of finger arrays. A second gate pad is electrically coupled to gate electrodes in the second set of finger arrays. A substrate is also provided on which are disposed the first and second set of finger arrays, the first and second source pads, the common drain pad, and the first and second gate pads.

Abstract: A semiconductor device and a method for fabricating the same are described. The semiconductor device includes a well of a first conductive type, first doped regions of a second conductive type, gates of the second conductive type, second doped regions of the first conductive type, and isolation structures. The well is disposed in a substrate. The first doped regions are disposed in the well. The first doped regions are arranged in parallel and extend along a first direction. The gates are disposed on the substrate. The gates are arranged in parallel and extend along a second direction different from the first direction. One of the first doped regions is electrically connected to one of the gates. Each of the second doped regions is disposed in the first doped regions between two adjacent gates. Each of the isolation structures is disposed in the substrate between two adjacent first doped regions.

Abstract: A semiconductor device with reduced defect density is fabricated by forming localized metal silicides instead of full area silicidation. Embodiments include forming a transistor having a gate electrode and source/drain regions on a substrate, forming a masking layer with openings exposing portions of both the gate electrode and source/drain regions over the substrate, depositing metal in the openings on the exposed portions, forming silicides in the openings, and removing unreacted metal and the masking layer.

Abstract: A method of fabricating a semiconductor device that includes forming a replacement gate structure on a portion of a semiconductor substrate, wherein source regions and drain regions are formed in opposing sides of the replacement gate structure. A dielectric is formed on the semiconductor substrate having an upper surface that is coplanar with an upper surface of the replacement gate structure. The replacement gate structure is removed to provide an opening to an exposed portion of the semiconductor substrate. A functional gate conductor is epitaxially grown within the opening in direct contact with the exposed portion of the semiconductor substrate. The method is applicable to planar metal oxide semiconductor field effect transistors (MOSFETs) and fin field effect transistors (finFETs).

Abstract: There is provided a low power memory device with JFET device structures. Specifically, a low power memory device is provided that includes a plurality memory cells having a memory element and a JFET access device electrically coupled to the memory element. The memory cells may be isolated using diffusion based isolation.

Abstract: A normally-off JFET is provided. The normally-off JFET includes a channel region of a first conductivity type, a floating semiconductor region of a second conductivity type adjoining the channel region, and a contact region of the first conductivity type adjoining the floating semiconductor region. The floating semiconductor region is arranged between the contact region and the channel region. Further, a normally-off semiconductor switch is provided.

Abstract: Devices and methods for providing JFET transistors with improved operating characteristics are provided. Specifically, one or more embodiments of the present invention relate to JFET transistors with a higher diode turn-on voltage. For example, one or more embodiments include a JFET with a PIN gate stack. One or more embodiments also relate to systems and devices in which the improved JFET may be employed, as well as methods of manufacturing the improved JFET.

Abstract: According to one embodiment, the semiconductor element includes a semi-insulating substrate which has a first first-conductivity-type layer. The semiconductor element includes a first semiconductor layer. The first semiconductor layer contains non-doped AlxGa1-XN (0?X<1). The semiconductor element includes a second semiconductor layer. The second semiconductor layer contains non-doped or second-conductivity-type AlYGa1-YN (0<Y?1 and X<Y)). The semiconductor element includes a first major electrode and a second major electrode. The semiconductor element includes a control electrode provided on the second semiconductor layer between the major electrodes. And the first first-conductivity-type layer is provided under the control electrode.

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

Abstract: A static induction transistor comprising: a region of semiconductor material having a first conductivity type; at least two spaced-apart gate regions formed in the region of semiconductor material, the gate regions having a second conductivity type that is opposite to the first conductivity type; at least one source region having the first conductivity type formed in the region of semiconductor material between the spaced-apart gate regions; a drain region having the first conductivity type formed in the region of semiconductor and spaced-apart from the source region to define a channel region therebetween; and a dielectric carrier separation layer formed at the periphery of the gate regions.

Abstract: A high-voltage junction field-effect transistor (JFET) includes a semiconductor substrate, a well region, first, second, and third doped regions, and first, second, and third terminals. The first doped region is disposed in the well region and the second dope region is laterally displaced from the well region. The third doped region is disposed in the well region between the first and second doped regions. A portion of the well region is substantially depleted of free charge carriers when a first voltage between the first and second terminals is greater than or equal to a pinch-off voltage. A voltage output at the third terminal is substantially proportional to the first voltage when the first voltage is less than the pinch-off voltage, and the voltage output at the third terminal is substantially fixed and less than the first voltage when the first voltage is greater than or equal to the pinch-off voltage.

Abstract: A semiconductor switch device and a method of manufacturing the semiconductor switch device are provided. The semiconductor switch device includes semiconductor elements on a single semiconductor substrate. At least one of the semiconductor elements constitutes a switch circuit and at least one other of the semiconductor elements constitutes a logic (connection) circuit. Each semiconductor element includes a recess, a gate electrode in the recess, a drain electrode, and a source electrode. In one representative aspect, the gate electrode in the switch circuit can have a rectangular external shape in section, and the gate electrode in the connection circuit has a shape in section other than rectangular.

Abstract: A semiconductor junction diode device structure and a method for manufacturing the same are provided, where a gate of the diode device structure is directly formed on the substrate, a P-N junction is formed in the semiconductor substrate, a first contact is formed on the gate, and a second contact is formed on the doped region at both sides of the gate, the first contact and the second contact acting as cathode/anode of the diode device, respectively. The diode device of this structure occupies a small area, and its forming process may be integrated in a gate-last integration process of MOSFET devices, which needs no additional mask and costs and has a high integration level.

Abstract: A low noise (1/f) junction field effect transistor (JFET) is disclosed, wherein multiple implants push a conduction path of the transistor away from the surface of a layer upon which the transistor is formed. In this manner, current flow in the conduction path is less likely to be disturbed by defects that may exist at the surface of the layer, thereby mitigating (1/f) noise.

Abstract: A semiconductor device includes: a gate electrode, a source electrode and a drain electrode, all of which are provided on top of a first surface of a substrate, and each of which includes multiple fingers; and an ohmic electrode layer. The semiconductor device includes: a gate terminal electrode connecting the fingers of the gate electrode together; a source terminal electrode connecting the fingers of the source electrode together; a drain terminal electrode connecting the fingers of the drain electrode together; and a gate pad placed on top of the ohmic electrode layer, and connecting the ohmic electrode layer to the gate terminal electrode. The semiconductor device further includes: an n type semiconductor layer formed in the substrate; a p type semiconductor layer formed in the n type semiconductor layer; and a reaction layer formed in the interface between the p type semiconductor layer substrate and the ohmic electrode layer.

Abstract: A plurality of gate structures are formed on a substrate. Each of the gate structures includes a first gate electrode and source and drain regions. The first gate electrode is removed from each of the gate structures. A first photoresist is applied to block gate structures having source regions in a source-down direction. A first halo implantation is performed in gate structures having source regions in a source-up direction at a first angle. The first photoresist is removed. A second photoresist is applied to block gate structures having source regions in a source-up direction. A second halo implantation is performed in gate structures having source regions in a source-down direction at a second angle. The second photoresist is removed. Replacement gate electrodes are formed in each of the gate structures.

Abstract: A junction field effect transistor of the present invention includes: a first conductivity type semiconductor substrate; a second conductivity type epitaxial layer formed on the semiconductor substrate; a first conductivity type epitaxial layer formed on the second conductivity type epitaxial layer; a second conductivity type source region which penetrates the first conductivity type epitaxial layer in a layer thickness direction thereof and is connected to the second conductivity type epitaxial layer; a second conductivity type drain region which is spaced from the source region, penetrates the first conductivity type epitaxial layer in the layer thickness direction, and is connected to the second conductivity type epitaxial layer; a source electrode connected to the source region; a drain electrode connected to the drain region; and a gate electrode electrically connected to the first conductivity type epitaxial layer between the source region and the drain region.

Abstract: The present invention has an object to provide an FET and a method of manufacturing the FET that are capable of increasing the threshold voltage as well as decreasing the on-resistance. The FET of the present invention includes a first undoped GaN layer; a first undoped AlGaN layer formed on the first undoped GaN layer, having a band gap energy greater than that of the first undoped GaN layer; a second undoped GaN layer formed on the first undoped AlGaN layer; a second undoped AlGaN layer formed on the second undoped GaN layer, having a band gap energy greater than that of the second undoped GaN layer; a p-type GaN layer formed in the recess of the second undoped AlGaN layer; a gate electrode formed on the p-type GaN layer; and a source electrode and a drain electrode which are formed in both lateral regions of the gate electrode, wherein a channel is formed at the heterojunction interface between the first undoped GaN layer and the first undoped AlGaN layer.

Abstract: A field effect transistor includes a GaN epitaxial substrate, a gate electrode formed on an electron channel layer of the substrate, and source and drain electrodes arranged spaced apart by a prescribed distance on opposite sides of the gate electrode. The source and drain electrodes are in ohmic contact with the substrate. At an upper portion of the gate electrode, a field plate is formed protruding like a visor to the side of drain electrode. Between the electron channel layer of the epitaxial substrate and the field plate, a dielectric film is formed. The dielectric film is partially removed at a region immediately below the field plate, to be flush with a terminal end surface of the field plate. The dielectric film extends from a lower end of the removed portion to the drain electrode, to be overlapped on the drain electrode.

Abstract: The invention provides a transistor having a leak current between a source and drain in a nitride compound semiconductor formed on a substrate that is reduced. A gate electrode, a source electrode and a drain electrode are formed respectively on the surface of the nitride compound semiconductor formed on the silicon substrate in the transistor. At least one of the source electrode and the drain electrode is surrounded by an auxiliary electrode connected with the gate electrode. Because a depletion layer is formed in the nitride compound semiconductor under the auxiliary electrode, a route of the leak current is shut off and the leak current between the source and drain may be effectively reduced.

Abstract: Double gate JFET with reduced area consumption and fabrication method therefore. Double-gate semiconductor device including a substrate having a shallow trench isolator region comprising a first STI and a second STI, a channel region having a first and second channel edges, the channel region formed in the substrate and disposed between and in contact with the first STI and the second STI at the first and second channel edge. The first STI has a first cavity at the first channel edge, and the second STI has a second cavity at the second channel edge. The device further includes a gate electrode region comprising conductive material filling at least one of the first and second cavities. At least one of the first and second cavities is physically configured to provide electrical coupling of the gate electrode region to a back-gate P-N junction.

Abstract: A semiconductor device includes: a substrate; and depletion and enhancement mode JFETs. The depletion mode JFET includes: a concavity on the substrate; a channel layer in the concavity; a first gate region on the channel layer; first source and drain regions on respective sides of the first gate region in the channel layer; first gate, source and drain electrodes. The enhancement mode JFET includes: a convexity on the substrate; the channel layer on the convexity; a second gate region on the channel layer; second source and drain regions on respective sides of the second gate region in the channel layer; second gate, source and drain electrodes. A thickness of the channel layer in the concavity is larger than a thickness of the channel layer on the convexity.

Abstract: Memory cells are constructed from double-gated four terminal transistors having independent gate control. DRAM cells using one transistor to implement a Ferroelectric FeRAM are described. Top gates provide conventional access while independent bottom gates provide control to optimize memory retention for given speed and power parameters as well as to accommodate hardening against radiation. In a single transistor cell without a capacitor, use of the bottom gate allows packing to a density approaching 2 F2. Using a ferroelectric material as the gate insulator produces a single-transistor FeRAM cell that overcomes the industry-wide Write Disturb problem. The memory cells are compatible with SOI logic circuitry for use as embedded RAM in SOC applications.

Abstract: An n type impurity region is continuously formed on the bottom portion of a channel region below a source region, a gate region and a drain region. The n type impurity region has an impurity concentration higher than the channel region and a back gate region, and is less influenced by the diffusion of p type impurities from the gate region and the back gate region. Moreover, by continuously forming the impurity region from a portion below the source region to a portion below the drain region, the resistance value of a current path in the impurity region is substantially uniformed. Therefore, the IDSS is stabilized, the forward transfer admittance gm and the voltage gain Gv are improved, and the noise voltage Vno is decreased. Furthermore, the IDSS variation within a single wafer is suppressed.

Abstract: A junction field effect transistor having a drain and a source, each defined by regions of a first type of semiconductor interconnected by a channel, and in which a dopant profile at a side of the drain facing the channel is modified so as to provide a region of reduced doping compared to a body region of the drain. The region of reduced doping and the body region can be defined by the same mask and doping step, but the mask is shaped to provide a lesser amount and thus less depth of doping for the region of reduced doping.

Abstract: A cascoded junction field transistor (JFET) device comprises a first stage high voltage JFET cascoded to a second stage low voltage JFET wherein one of the first and second stages JFET is connected to a drain electrode of another JFET stage.

Abstract: This invention describes a method of building complementary logic circuits using junction field effect transistors in silicon. This invention is ideally suited for deep submicron dimensions, preferably below 65 nm. The basis of this invention is a complementary Junction Field Effect Transistor which is operated in the enhancement mode. The speed-power performance of the JFETs becomes comparable with the CMOS devices at sub-70 nanometer dimensions. However, the maximum power supply voltage for the JFETs is still limited to below the built-in potential (a diode drop). To satisfy certain applications which require interface to an external circuit driven to higher voltage levels, this invention includes the structures and methods to build CMOS devices on the same substrate as the JFET devices.

Abstract: A method (100) of forming semiconductor structures (202) including high-temperature processing steps (step 118), incorporates the use of a high-temperature nitride-oxide mask (220) over protected regions (214) of the device (202). The invention has application in many different embodiments, including but not limited to, the formation of recess, strained device regions (224).

Abstract: A bulk GaN layer is on a first surface of a substrate, wherein the bulk GaN layer has a GaN transistor region and a bulk acoustic wave (BAW) device region. A source/drain layer is over a first surface of the bulk GaN layer in the GaN transistor region. A gate electrode is formed over the source/drain layer. A first BAW electrode is formed over the first surface of the bulk GaN layer in the BAW device region. An opening is formed in a second surface of the substrate, opposite the first surface of the substrate, which extends through the substrate and exposes a second surface of the bulk GaN layer, opposite the first surface of the bulk GaN layer. A second BAW electrode is formed within the opening over the second surface of the bulk GaN layer.

Abstract: A semiconductor device 100 includes: a semiconductor substrate 10 of silicon carbide of a first conductivity type; a silicon carbide epitaxial layer 20 of the first conductivity type, which has been grown on the principal surface 10a of the substrate 10; well regions 22 of a second conductivity type, which form parts of the silicon carbide epitaxial layer 20; and source regions 24 of the first conductivity type, which form respective parts of the well regions 22. A channel epitaxial layer 30 of silicon carbide has been grown over the well regions 22 and source regions 24 of the silicon carbide epitaxial layer 20. A portion of the channel epitaxial layer 30 that is located over the well regions 22 functions as a channel region 40. And a dopant of the first conductivity type has been implanted into the other portions 33 and 35 of the channel epitaxial layer 30 except the channel region 40.