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 method includes forming a relaxed layer in a semiconductor device. The method also includes forming a tensile layer over the relaxed layer, where the tensile layer has tensile stress. The method further includes forming a compressive layer over the relaxed layer, where the compressive layer has compressive stress. The compressive layer has a piezoelectric polarization that is approximately equal to or greater than a spontaneous polarization in the relaxed, tensile, and compressive layers. The piezoelectric polarization in the compressive layer could be in an opposite direction than the spontaneous polarization in the compressive layer. The relaxed layer could include gallium nitride, the tensile layer could include aluminum gallium nitride, and the compressive layer could include aluminum indium gallium nitride.

Abstract: An AlGaN/GaN-HEMT has a structure including: compound semiconductor layers formed on a substrate; a gate electrode, a gate pad that has a current path formed between the gate electrode and itself, and a semiconductor layer that is spontaneously polarized and piezoelectrically polarized, which are formed on the compound semiconductor layer; and a gate electrode connection layer formed on the semiconductor layer, wherein the gate electrode connection layer and the gate electrode are electrically connected with each other. This structure which is relatively simple allows the AlGaN/GaN-HEMT to realize an intended normally-off operation without causing such inconveniences as increase in a sheet resistance, increase in an on-resistance, and increase in a leakage current.

Abstract: A preferred method of optimizing a Ga-nitride device material structure for a frequency multiplication device comprises: determining the amplitude and frequency of the input signal being multiplied in frequency; providing a Ga-nitride region on a substrate; determining the Al percentage composition and impurity doping in an AlGaN region positioned on the Ga-nitride region based upon the power level and waveform of the input signal and the desired frequency range in order to optimize power input/output efficiency; and selecting an orientation of N-face polar GaN or Ga-face polar GaN material relative to the AlGaN/GaN interface so as to orient the face of the GaN so as to optimize charge at the AlGaN/GaN interface. A preferred embodiment comprises an anti-serial Schottky varactor comprising: two Schottky diodes in anti-serial connection; each comprising at least one GaN layer designed based upon doping and thickness to improve the conversion efficiency.

Abstract: Methods for forming a HEMT device are provided. The method includes forming an ultra-thin barrier layer on the plurality of thin film layers. A dielectric thin film layer is formed over a portion of the ultra-thin barrier layer to leave exposed areas of the ultra-thin barrier layer. A SAG S-D thin film layer is formed over the exposed areas of the ultra-thin barrier layer while leaving the dielectric thin film layer exposed. The dielectric thin film layer is then removed to expose the underlying ultra-thin barrier layer. The underlying ultra-thin barrier layer is treating with fluorine to form a treated area. A source and drain is added on the SAG S-D thin film layer, and a dielectric coating is deposited over the ultra-thin barrier layer treated with fluorine such that the dielectric coating is positioned between the source and the drain.

Abstract: There are disclosed herein various implementations of a semiconductor structure and method. The semiconductor structure comprises a substrate, a transition body over the substrate, and a group III-V intermediate body having a bottom surface over the transition body. The semiconductor structure also includes a group III-V device layer over a top surface of the group III-V intermediate body. The group III-V intermediate body has a continuously reduced impurity concentration wherein a higher impurity concentration at the bottom surface is continuously reduced to a lower impurity concentration at the top surface.

Abstract: High electron mobility transistors (HEMTs) and methods of manufacturing the same. A HEMT may include a channel layer and a channel supply layer, and the channel supply layer may be a multilayer structure. The channel supply layer may include an etch stop layer and an upper layer on the etch stop layer. A recess region may be in the upper layer. The recess region may be a region recessed to an interface between the upper layer and the etch stop layer. A gate electrode may be on the recess region.

Abstract: A semiconductor structure is provided, comprising: a Si substrate; a porous structure layer formed on the Si substrate, in which the porous structure layer has a flat surface and comprises a Si1-xGex layer with low Ge content; and a Ge-containing layer formed on the porous structure layer, in which the Ge containing layer comprises a Ge layer or a Si1-yGey layer with high Ge content and x?y. Further, a method for forming the semiconductor structure is also provided.

Abstract: The present disclosure relates to a channel layer of bi-layer of gallium nitride (GaN) within a HEMT. A first breakdown voltage layer of GaN is disposed beneath an active layer of the HEMT. A second breakdown voltage layer of GaN is disposed beneath the first breakdown voltage layer, wherein the first resistivity value is less than the second resistivity value. An increased resistivity of the second breakdown voltage layer results from an increased concentration of carbon dopants which increases the breakdown voltage in the second breakdown voltage layer, but can degrade the crystal structure. To alleviate this degradation, a crystal adaptation layer is disposed beneath the second breakdown voltage layer and configured to lattice-match to the second breakdown voltage layer of GaN. As a result, the HEMT achieves a high breakdown voltage without any associated degradation to the first breakdown voltage layer, wherein a channel of the HEMT resides.

Abstract: The present disclosure relates to a gallium-nitride (GaN) transistor device having a composite gallium nitride layer with alternating layers of GaN and aluminum nitride (AlN). In some embodiments, the GaN transistor device has a first GaN layer disposed above a semiconductor substrate. An AlN inter-layer is disposed on the first GaN layer. A second GaN layer is disposed on the AlN inter-layer. The AlN inter-layer allows for the thickness of the GaN layer to be increased over continuous GaN layers, mitigating bowing and cracking of the GaN substrate, while improving the breakdown voltage of the disclosed GaN device.

Abstract: A III-V semiconductor device on a silicon substrate is constructed with a silicon (Si) substrate onto which gallium arsenide (GaAs) indium phosphide (InP) and aluminum indium arsenide (AlInAs) to form a structure of AlInAs over InP over GaAs over Si. The GaAs is applied in at least one layer over the Si, followed by at least one layer of InP and at least one layer of AlInAs. A portion of the structure is doped and a cap or passivation layer is applied.

Abstract: Some exemplary embodiments of high voltage cascoded III-nitride semiconductor package utilizing clips on a package support surface have been disclosed. One exemplary embodiment comprises a III-nitride transistor attached to a package support surface and having an anode of a diode stacked over a source of the III-nitride transistor, a first conductive clip coupled to a gate of the III-nitride transistor and the anode of the diode, and a second conductive clip coupled to a drain of the III-nitride transistor. The conductive clips are connected to the package support surface and expose respective flat portions that are surface mountable. In this manner, reduced package footprint, improved surge current capability, and higher performance may be achieved compared to conventional wire bonded packages. Furthermore, since a low cost printed circuit board (PCB) may be utilized for the package support surface, expensive leadless fabrication processes may be avoided for cost effective manufacturing.

Abstract: The present disclosure relates to a donor layer of bi-layer AlGaN and associated method of fabrication within a high electron mobility transistor (HEMT) configured to provide low-resistance ohmic source and drain contacts to reduce power consumption, while maintaining a high-mobility of a two-dimensional electron gas (2DEG) within a channel of the HEMT. The donor layer of bi-layer AlGaN comprises a mobility-enhancing layer of AlzGa(1-z)N, a resistance-reducing layer of AlxGa(1-x)N disposed over the mobility-enhancing layer, wherein the ohmic source and drain contacts connect to the HEMT. A channel layer of GaN is disposed beneath the mobility-enhancing layer, wherein a 2DEG resides, forming the channel of the HEMT.

Abstract: A compound semiconductor device includes: a compound semiconductor multilayer structure; a gate insulating film on the compound semiconductor multilayer structure; and a gate electrode, wherein the gate electrode includes a gate base portion on the gate insulating film and a gate umbrella portion, and a surface of the gate umbrella portion includes a Schottky contact with the compound semiconductor multilayer structure.

Abstract: A semiconductor device includes: a semiconductor layer disposed above a substrate; an insulating film formed by oxidizing a portion of the semiconductor layer; and an electrode disposed on the insulating film, wherein the insulating film includes gallium oxide, or gallium oxide and indium oxide.

Abstract: Provided is a nitride electronic device having a structure that allows the reduction of leakage by preventing the carrier concentration from increasing in a channel layer. An inclined surface and a primary surface of a semiconductor stack extend along first and second reference planes R1, R2, respectively. The primary surface of the stack is inclined at an angle ranging from 5 to 40 degrees with respect to a reference axis indicating a c-axis direction of hexagonal group III nitride. An axis normal to the plane R1 and the axis form an angle smaller than the angle an axis normal to the plane R2 and the axis form. The oxygen concentration of the channel layer is lower than 1×1017 cm?3. It becomes possible to avoid increase in carrier concentration of the channel layer caused by the oxygen addition, thereby reducing leakage current via the channel layer in the transistor.

Abstract: A low-loss GaN-based semiconductor device is provided. The semiconductor device has the InzGa1-zN layer (where 0?z<1), the AlxGa1-xN layer (where 0<x<1), the InyGa1-yN layer (where 0?y<1) and the p-type InwGa1-wN layer (where 0?w<1) which are sequentially stacked on a base substrate of a C-plane sapphire substrate, etc. At a non-operating time, the two-dimensional hole gas is formed in the InyGa1-yN layer in the vicinity part of a hetero-interface between the AlxGa1-xN layer and the InyGa1-yN layer, and the two-dimensional electron gas is formed in the InzGa1-zN layer in the vicinity part of a hetero-interface between the InzGa1-zN layer and the AlxGa1-xN layer.

Abstract: There are disclosed herein various implementations of semiconductor structures including one or more spatially confined dielectric regions. In one exemplary implementation, such a semiconductor structure includes a III-Nitride field-effect transistor (FET) having a drain, a source, and a gate, fabricated over a substrate. A spatially confined dielectric region is formed under the drain in the substrate, the spatially confined dielectric region reducing a capacitive coupling of the drain to the substrate. In another exemplary implementation, a spatially confined dielectric region is formed under each of the source and the drain of the FET, in the substrate, the spatially confined dielectric regions reducing a capacitive coupling of the source and the drain to the substrate.

Abstract: A semiconductor device includes: a compound semiconductor stack structure including a plurality of compound semiconductor layers stacked over a semiconductor substrate; a first insulating film covering the surface of the compound semiconductor stack structure; and a conductive film provided on the surface of the first insulating film.

Abstract: Provided is a field-effect transistor including a gate insulating layer, a first semiconductor crystal layer in contact with the gate insulating layer, and a second semiconductor crystal layer lattice-matching or pseudo lattice-matching the first semiconductor crystal layer. Here, the gate insulating layer, the first semiconductor crystal layer, and the second semiconductor crystal layer are arranged in the order of the gate insulating layer, the first semiconductor crystal layer, and the second semiconductor crystal layer, the first semiconductor crystal layer is made of Inx1Ga1-x1Asy1P1-y1 (0<x1?1, 0?y1?1), the second semiconductor crystal layer is made of Inx2Ga1-x2Asy2P1-y2 (0?x2?1, 0?y2?1, y2?y1), and the electron affinity Ea1 of the first semiconductor crystal layer is lower than the electron affinity Ea2 of the second semiconductor crystal layer.

Abstract: Embodiments include but are not limited to apparatuses and systems including a buffer layer, a group III-V layer over the buffer layer, a source contact and a drain contact on the group III-V layer, and a regrown Schottky layer over the group III-V layer, and between the source and drain contacts. The embodiments further include methods for making the apparatuses and systems. Other embodiments may be described and claimed.

Abstract: A semiconductor device including a first lattice dimension III-V semiconductor layer present on a semiconductor substrate, and a second lattice dimension III-V semiconductor layer that present on the first lattice dimension III-V semiconductor layer, wherein the second lattice dimension III-V semiconductor layer has a greater lattice dimension than the first lattice dimension III-V semiconductor layer, and the second lattice dimension III-V semiconductor layer has a compressive strain present therein. A gate structure is present on a channel portion of the second lattice dimension III-V semiconductor layer, wherein the channel portion of second lattice dimension III-V semiconductor layer has the compressive strain. A source region and a drain region are present on opposing sides of the channel portion of the second lattice dimension III-V semiconductor layer.

Abstract: A method for manufacturing a semiconductor device includes forming an electron transit layer on a semiconductor substrate, forming an electron supply layer on the electron transit layer, forming a cap layer on the electron supply layer, forming a protection layer on the cap layer, the protection layer having an opening part, through which a part of the cap layer is exposed, and forming an oxidation film on an exposed surface of the cap layer by a wet process.

Abstract: According to example embodiments, a HEMT includes a channel layer, a channel supply layer on the channel layer, a source electrode and a drain electrode spaced apart on the channel layer, a depletion-forming layer on the channel supply layer, and a plurality of gate electrodes on the depletion-forming layer between the source electrode and the drain electrode. The channel supply layer is configured to induce a two-dimensional electron gas (2DEG) in the channel layer. The depletion-forming layer is configured to form a depletion region in the 2DEG. The plurality of gate electrodes include a first gate electrode and a second gate electrode spaced apart from each other.

Abstract: To provide a semiconductor device in which a rectifying element capable of reducing a leak current in reverse bias when a high voltage is applied and reducing a forward voltage drop Vf and a transistor element are integrally formed on a single substrate. A semiconductor device has a transistor element and a rectifying element on a single substrate. The transistor element has an active layer formed on the substrate and three electrodes (source electrode, drain electrode, and gate electrode) disposed on the active layer. The rectifying element has an anode electrode disposed on the active layer, a cathode electrode which is the drain electrode, and a first auxiliary electrode between the anode electrode and cathode electrode.

Abstract: A method of forming a semiconductor structure having a substrate is disclosed. The semiconductor structure includes a first layer formed in contact with the substrate. The first layer made of a first III-V semiconductor material selected from GaN, GaAs and InP. A second layer is formed on the first layer. The second layer made of a second III-V semiconductor material selected from AlGaN, AlGaAs and AlInP. An interface is between the first layer and the second layer forms a carrier channel. An insulating layer is formed on the second layer. Portions of the insulating layer and the second layer are removed to expose a top surface of the first layer. A metal feature is formed in contact with the carrier channel and the metal feature is annealed to form a corresponding intermetallic compound.

Abstract: The present invention discloses a high electron mobility transistor (HEMT) and a manufacturing method thereof. The HEMT includes a semiconductor layer, a barrier layer on the semiconductor layer, a piezoelectric layer on the barrier layer, a gate on the piezoelectric layer, and a source and a drain at two sides of the gate respectively, wherein each bandgap of the semiconductor layer, the barrier layer, and the piezoelectric layer partially but not entirely overlaps the other two bandgaps. The gate is formed for receiving a gate voltage. A two dimensional electron gas (2DEG) is formed in a portion of a junction between the semiconductor layer and the barrier layer but not below at least a portion of the piezoelectric layer, wherein the 2DEG is electrically connected to the source and the drain.

Abstract: A semiconductor structure includes a first III-V compound layer. A second III-V compound layer is disposed on the first III-V compound layer and is different from the first III-V compound layer in composition. A dielectric passivation layer is disposed on the second III-V compound layer. A source feature and a drain feature are disposed on the second III-V compound layer, and extend through the dielectric passivation layer. A gate electrode is disposed over the second III-V compound layer between the source feature and the drain feature. The gate electrode has an exterior surface. An oxygen containing region is embedded at least in the second III-V compound layer under the gate electrode. A gate dielectric layer has a first portion and a second portion. The first portion is under the gate electrode and on the oxygen containing region. The second portion is on a portion of the exterior surface of the gate electrode.

Abstract: A gate electrode is formed so as to embed an electrode material in a recess for an electrode, which has been formed in a structure of stacked compound semiconductors, through a gate insulation film, and also a field plate electrode that comes in Schottky contact with the structure of the stacked compound semiconductors is formed by embedding an electrode material in a recess for an electrode, which has been formed in the structure of the stacked compound semiconductors so that the field plate electrode directly comes in contact with the structure of the stacked compound semiconductors at least on the bottom face of the recess for the electrode.

Abstract: A method of fabricating a GaN HEMT includes growing a first epitaxial layer on a substrate, growing a second epitaxial layer on the first epitaxial layer, growing a third epitaxial layer on the second epitaxial layer, depositing a first dielectric film on the third epitaxial layer, using dielectric films to form a first sidewall dielectric spacer, forming a sidewall gate adjacent the first sidewall dielectric spacer. The sidewall gate may be made to be less than 50 nm in length.

Abstract: A semiconductor device has a stacked structure in which a p-GaN layer, an SI-GaN layer, and an AlGaN layer are stacked, and has a gate electrode that is formed at a top surface side of the AlGaN layer. A band gap of the AlGaN layer is wider than a band gap of the p-GaN layer and the SI-GaN layer. Moreover, impurity concentration of the SI-GaN layer is less than 1×1017 cm?3. Semiconductor devices including III-V semiconductors may have a stable normally-off operation.

Abstract: A heterostructure field effect transistor (HFET) gallium nitride (GaN) semiconductor power device comprises a hetero-junction structure comprises a first semiconductor layer interfacing it second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer. The power device further comprises a source electrode and a drain electrode disposed on two opposite sides of a gate electrode disposed on top of the hetero-junction structure for controlling a current flow between the source and drain electrodes in the 2DEG layer.

Abstract: A semiconductor device includes: a first transistor that includes a first gate electrode, a first source electrode, a first drain electrode, and a first nitride semiconductor laminate that includes a first electron transit layer and a first electron supply layer; a second transistor that includes a second gate electrode, a second source electrode, a second drain electrode, and a second nitride semiconductor laminate that includes a second electrode transit layer and a second electron supply layer, the second drain electrode being a common electrode that also serves as the first source electrode, the second electron transit layer having part that underlies the second gate electrode and that contains a p-type dopant; and a p-type-dopant-diffusion-blocking layer.

Abstract: A ring-shaped transistor includes a set of gates. Each gate of the set is disposed between a corresponding source and a corresponding drain. The set of gates are arranged such that all of the set of gates cannot be aligned with fewer than three imaginary straight lines drawn through the gates, with one of the imaginary straight lines passing only once though each of the set of gates.

Abstract: The invention relates to a method for producing silicon semiconductor wafers and components having layer structures of III-V layers for integrating III-V semiconductor components. The method employs SOI silicon semiconductor wafers having varying substrate orientations, and the III-V semiconductor layers are produced in trenches (28, 43, 70) produced by etching within certain regions (38, 39), which are electrically insulated from each other, of the active semiconductor layer (24, 42) by means of a cover layer or cover layers (29) using MOCVD methods.

Abstract: Disclosed are methods of growing III-V epitaxial layers on a substrate, semiconductor structures thus obtained, and devices comprising such semiconductor structures. An example semiconductor substrate includes a substrate and a buffer layer on top of the substrate, where a conductive path is present between the substrate and buffer layer. A conductive path may be present in the conductive interface, and the conductive path may be interrupted by one or more local electrical isolations. The local electrical isolation(s) may be positioned with the device such that at least one of the local electrical isolation(s) is located between a high voltage terminal and a low voltage terminal of the device.

Abstract: A field effect transistor includes an active layer and a capping layer sequentially stacked on a substrate, and a gate electrode penetrating the capping layer and being adjacent to the active layer. The gate electrode includes a foot portion adjacent to the active layer and a head portion having a width greater than a width of the foot portion. The foot portion of an end part of the gate electrode has a width less than a width of the head portion of another part of the gate electrode and greater than a width of the foot portion of the another part of the gate electrode. The foot portion of the end part of the gate electrode further penetrates the active layer so as to be adjacent to the substrate.

Abstract: A method comprises epitaxially growing a gallium nitride (GaN) layer over a silicon substrate, epitaxially growing a donor-supply layer over the GaN layer, and etching a portion of the donor-supply layer. The method also comprises depositing a passivation layer over the donor-supply layer and filling the etched portion of the donor-supply layer, forming a source and a drain on the donor-supply layer, and forming a gate structure between the source and the etched portion of the donor-supply layer. The method further comprises depositing contacts over the gate structure, the source, and the drain.

Abstract: Disclosed are methods of growing III-V epitaxial layers on a substrate, a semiconductor structure comprising a substrate, a device comprising such a semiconductor structure, and an electronic circuit. Group III-nitride devices, such as, for example, high-electron-mobility transistors, may include a two-dimensional electron gas (2DEG) between two active layers. For example, the 2DEG may be between a GaN layer and a AlGaN layer. These transistors may work in depletion-mode operation, which means the channel has to be depleted to turn the transistor off. For certain applications, such as, for example, power switching or integrated logic, negative polarity gate supply is undesired. Transistors may then work in enhancement mode (E-mode).

Abstract: A high electron mobility transistor includes a T-type gate electrode disposed on a substrate between source and drain electrodes and insulating layers disposed between the substrate and the T-type gate electrode. The insulating layers include first, second, and third insulating layers. The third insulating layer is disposed between the substrate and a head portion of the T-type gate electrode such that a portion of the third insulating layer is in contact with a foot portion of the T-type gate electrode. The second insulating layer is disposed between the substrate and the head portion of the T-type gate electrode to be in contact with the third insulating layer. The first insulating layer and another portion of the third insulating layer are sequentially stacked between the substrate and the head portion of the T-type gate electrode to be in contact with the second insulating layer.

Abstract: A semiconductor structure includes a III-nitride substrate with a first side and a second side opposing the first side. The III-nitride substrate is characterized by a first conductivity type and a first dopant concentration. The semiconductor structure also includes a III-nitride epitaxial layer of the first conductivity type coupled to the first surface of the III-nitride substrate, and a first metallic structure electrically coupled to the second surface of the III-nitride substrate. The semiconductor structure further includes an AlGaN epitaxial layer coupled to the III-nitride epitaxial layer of the first conductivity type, and a III-nitride epitaxial structure of a second conductivity type coupled to the AlGaN epitaxial layer. The III-nitride epitaxial structure comprises at least one edge termination structure.

Abstract: Disclosed are semiconductor devices and methods for manufacturing them. An example device may include a III-nitride stack having a front side surface and a back side surface. The III-nitride stack may be formed of at least a first layer and a second layer, between which a heterojunction may be formed, such that a two-dimensional electron gas layer is formed in the second layer. A source electrode, a drain electrode, and a gate electrode positioned between the source and drain electrodes may be formed on the front side surface, and an insulation layer may be formed over the electrodes on the front side surface. A carrier substrate may be attached to the insulation layer. An electrically conductive back plate may be formed on the back side surface. The back plate may directly face the source electrode and the gate electrode, but not the drain electrode.

Abstract: A semiconductor device includes a channel layer; and a high resistance layer that is provided on the channel layer, and is made of a semiconductor with high resistance which has a conduction band position higher than that of the semiconductor which forms the channel layer. The semiconductor device includes a first conduction-type low resistance region provided on a surface layer of the high resistance layer, and is made of a semiconductor including first conduction type impurities. The semiconductor device includes: a source electrode and a drain electrode that are connected to the high resistance layer, in a position crossing the low resistance region; a gate insulating film provided on the low resistance region; and a gate electrode provided on the low resistance region via the gate insulating film. The semiconductor device includes current block regions between the low resistance region, and between the source electrode and the drain electrode respectively.

Abstract: A field effect transistor is provided. The field effect transistor may include a capping layer on a substrate, a source ohmic electrode and a drain ohmic electrode on the capping layer, a first insulating layer and a second insulating layer stacked on the capping layer to cover the source and drain ohmic electrodes, a ?-shaped gate electrode including a leg portion and a head portion, the leg portion being connected to the substrate between the source ohmic electrode and the drain ohmic electrode, and the head portion extending from the leg portion to cover a top surface of the second insulating layer, a first planarization layer on the second insulating layer to cover the ?-shaped gate electrode, and a first electrode on the first planarization layer, the first electrode being connected to the source ohmic electrode or the drain ohmic electrode.

Abstract: The present invention discloses a high electron mobility transistor (HEMT) and a manufacturing method thereof. The HEMT device includes: a substrate, a first gallium nitride (GaN) layer; a P-type GaN layer, a second GaN layer, a barrier layer, a gate, a source, and a drain. The first GaN layer is formed on the substrate, and has a stepped contour from a cross-section view. The P-type GaN layer is formed on an upper step surface of the stepped contour, and has a vertical sidewall. The second GaN layer is formed on the P-type GaN layer. The barrier layer is formed on the second GaN layer. two dimensional electron gas regions are formed at junctions between the barrier layer and the first and second GaN layers. The gate is formed on an outer side of the vertical sidewall.

Abstract: The present invention relates to fabrication of enhancement mode and depletion mode High Electron Mobility Field Effect Transistors on the same die separated by as little as 10 nm. The fabrication method uses selective decomposition and selective regrowth of the Barrier layer and the Cap layer to engineer the bandgap of a region on a die to form an enhancement mode region. In these regions zero or more devices may be fabricated.

Abstract: A method for fabricating a semiconductor device includes forming ohmic electrodes on a source region and a drain region of a nitride semiconductor layer, forming a low-resistance layer between an uppermost surface of the nitride semiconductor layer and the ohmic electrodes by annealing the nitride semiconductor layer, removing the ohmic electrodes from at least one of the source region and the drain region after forming the low-resistance layer, and forming at least one of a source electrode and a drain electrode on the low-resistance layer, the at least one of a source electrode and a drain electrode having an edge, a distance between the edge and a gate electrode is longer than a distance between an edge of the low-resistance layer and the gate electrode.

Abstract: An epitaxial structure, such as an enhancement-mode high electron mobility transistor (HEMT) includes a first barrier layer over an aluminum gallium nitride channel layer. The first barrier layer is formed at a first temperature and is overlaid by a second barrier layer formed at a second temperature that is lower than that of the first temperature. The first barrier layer acts as an etch stop when forming a gate recess in the second barrier layer by a wet or dry etching.

Abstract: The compound semiconductor device includes a first-compound-semiconductor-layer, a second-compound-semiconductor-layer formed on an upper side of the first-compound-semiconductor-layer and having a band gap larger than the band gap of the first-compound-semiconductor-layer, a p-type third-compound-semiconductor-layer formed on an upper side of the second-compound-semiconductor-layer, an electrode formed on an upper side of the second-compound-semiconductor-layer through the third-compound-semiconductor-layer, a fourth-compound-semiconductor-layer formed so as to be in contact with the third-compound-semiconductor-layer at an upper side of the second-compound-semiconductor-layer and having a band gap smaller than the band gap of the second-compound-semiconductor-layer, and a fifth-compound-semiconductor-layer formed so as to be in contact with the third-compound-semiconductor-layer at an upper side of the fourth-compound-semiconductor-layer and having a band gap larger than the band gap of the fourth-compound-

Abstract: A method is provided for fabricating a transistor. The method includes providing a semiconductor substrate, and forming a quantum well layer on the semiconductor substrate. The method also includes forming a potential energy barrier layer on the semiconductor substrate, and forming an isolation structure to isolate different transistor regions. Further, the method includes patterning the transistor region to form trenches by removing portions of the quantum well layer and the potential energy barrier layer corresponding to a source region and a drain region, and filling trenches with a semiconductor material to form a source and a drain. Further, the method also includes forming a gate structure on a portion of the quantum well layer and the potential energy barrier layer corresponding to a gate region.