Abstract: Gallium nitride material structures are provided, as well as devices and methods associated with such structures. The structures include a diamond region which may facilitate conduction and removal of heat generated within the gallium nitride material during device operation. The structures described herein may form the basis of a number of semiconductor devices and, in particular, transistors (e.g., FETs).

Abstract: Disclosed is a III-nitride heterojunction device that includes a conduction channel having a two dimensional electron gas formed at an interface between a first III-nitride material and a second III-nitride material. A modification including a contact insulator, for example, a gate insulator formed under a gate contact, is disposed over the conduction channel, wherein the contact insulator includes aluminum to alter formation of the two dimensional electron gas at the interface. The contact insulator can include AlSiN, or can be SiN doped with aluminum. The modification results in programming the threshold voltage of the III-nitride heterojunction device to, for example, make the device an enhancement mode device. The modification can further include a recess, an ion implanted region, a diffused region, an oxidation region, and/or a nitridation region. In one embodiment, the first III-nitride material comprises GaN and the second III-nitride material comprises AlGaN.

Abstract: A compound semiconductor epitaxial substrate having a pseudomorphic high electron mobility field effect transistor structure including an InGaAs layer as a strained channel layer and an AlGaAs layer containing n type impurities as a front side electron-donating layer, wherein said substrate contains an InGaP layer in an orderly state on the front side of the above described InGaAs layer as the strained channel layer.

Abstract: A semiconductor device, and particularly a high electron mobility transistor (HEMT), having a plurality of epitaxial layers and experiencing an operating (E) field. A negative ion region in the epitaxial layers to counter the operating (E) field. One method for fabricating a semiconductor device comprises providing a substrate and growing epitaxial layers on the substrate. Negative ions are introduced into the epitaxial layers to form a negative ion region to counter operating electric (E) fields in the semiconductor device. Contacts can be deposited on the epitaxial layers, either before or after formation of the negative ion region.

Abstract: A GaN heterojunction FET has an AlxGa1-xN first graded layer and an AlyGa1-yN second graded layer, which are formed sequentially on a channel layer. The Al mole fraction x of the first graded layer decreases linearly from, for example, 0.2 at an interface of the first graded layer with the channel layer to 0.1 at an interface thereof with the second graded layer. The Al mole fraction y of the second graded layer increases from, for example, 0.1 at an interface of the second graded layer with the first graded layer to 0.35 at a surface located on the opposite side from the first graded layer. Because the intrinsic polarization of AlGaN depends on the Al mole fraction, fixed negative charge is generated in the AlxGa1-xN first graded layer, and fixed positive charge is generated in the AlyGa1-yN second graded layer.

Abstract: A semiconductor device is provided that includes a substrate, a first active layer disposed over the substrate, and a second active layer disposed on the first active layer. The second active layer has a higher bandgap than the first active layer such that a two-dimensional electron gas layer arises between the first active layer and the second active layer. A termination layer, which is disposed on the second active layer, includes InGaN. Source, gate and drain contacts are disposed on the termination layer.

Abstract: In one embodiment, the disclosure relates to an electronic device successively comprising from its base to its surface: (a) a support layer, (b) a channel layer adapted to contain an electron gas, (c) a barrier layer and (d) at least one ohmic contact electrode formed by a superposition of metallic layers, a first layer of which is in contact with the barrier layer. The device is remarkable in that the barrier layer includes a contact region under the ohmic contact electrode(s). The contact region includes at least one metal selected from the metals forming the superposition of metallic layers. Furthermore, a local alloying binds the contact region and the first layer of the electrode(s).

Abstract: A field effect transistor includes a semiconductor stack formed on a substrate, and having a first nitride semiconductor layer and a second nitride semiconductor layer. A source electrode and a drain electrode are formed on the semiconductor stack so as to be separated from each other. A gate electrode is formed between the source electrode and the drain electrode so as to be separated from the source electrode and the drain electrode. A hole injection portion is formed near the drain electrode. The hole injection portion has a p-type third nitride semiconductor layer, and a hole injection electrode formed on the third nitride semiconductor layer. The hole injection electrode and the drain electrode have substantially the same potential.

Abstract: High electron mobility transistors (HEMT) exhibiting dual depletion and methods of manufacturing the same. The HEMT includes a source electrode, a gate electrode and a drain electrode disposed on a plurality of semiconductor layers having different polarities. A dual depletion region exists between the source electrode and the drain electrode. The plurality of semiconductor layers includes an upper material layer, an intermediate material layer and a lower material layer, and a polarity of the intermediate material layer is different from polarities of the upper material layer and the lower material layer.

Abstract: A high electron mobility transistor includes a free-standing supporting base having a III nitride region, a first III nitride barrier layer which is provided on the first III nitride barrier layer, a III nitride channel layer which is provided on the first III nitride barrier layer and forms a first heterojunction with the first III nitride barrier layer, a gate electrode provided on the III nitride channel layer so as to exert an electric field on the first heterojunction, a source electrode on the III nitride channel layer and the first III nitride barrier, and a drain electrode on the III nitride channel layer and the first III nitride barrier. The III nitride channel layer has compressive internal strain, and the piezoelectric field of the III nitride channel layer is oriented in the direction from the supporting base towards the first III nitride barrier layer.

Abstract: A semiconductor device is described. In one embodiment, the device includes a Group-III nitride channel layer and a Group-III nitride barrier layer on the Group-III nitride channel layer, wherein the Group-III nitride barrier layer includes a first portion and a second portion, the first portion having a thickness less than the second portion. A p-doped Group-III nitride gate layer section is arranged at least on the first portion of the Group-III nitride barrier layer and a gate contact formed on the p-doped Group-III nitride gate layer.

Abstract: A normally-off operation type HEMT device excellent in characteristics can be realized. A two-dimensional electron gas region is formed in a periphery of a hetero-junction interface of a base layer and a barrier layer, so that access resistance in an access portion, that is, between a drain and a gate and between a gate and a source is sufficiently lowered, and at the same time, a P-type region is formed immediately under the gate. This realizes a normally-off type HEMT device having a low on-resistance. Further, when a film thickness of an insulating layer is defined as t (nm) and a relative permittivity of a substance forming the insulating layer is defined as k, a threshold voltage as high as +3 V or more can be attained by satisfying k/t?0.85 (nm?1).

Abstract: A nitride semiconductor device including: a substrate; a nitride semiconductor layer formed on the substrate and having a heterojunction interface; and a recess portion formed on the nitride semiconductor layer, wherein the nitride semiconductor layer includes: a carrier transit layer, which has a composition represented by the formula: Alx1Inx2Ga1-x1-x2N, (0?x1?1, 0?x2?1, 0?(x1+x2)?1); and a carrier supply layer including: a first layer formed on the carrier transit layer, said first layer having a composition represented by the formula: AlyGa1-yN, (0<y?1, x1<y); a second layer formed on the first layer, said second layer containing GaN; and a third layer formed on the second layer, said third layer having a composition represented by the formula: AlzGa1-zN, (0<z?1, x1<z), and wherein the recess portion is formed to penetrate the third layer and expose a surface of the second layer at a bottom portion of the recess portion.

Abstract: A terahertz wave radiating element includes: a first nitride semiconductor layer formed on a substrate; a second nitride semiconductor layer formed over the first nitride semiconductor layer, and having a wider bandgap than the first nitride semiconductor layer; and source, gate, and drain electrodes formed on the second nitride semiconductor layer. The source electrode is formed by a plurality of source electrode fingers that are arranged periodically, and the drain electrode is formed by a plurality of drain electrode fingers that are arranged periodically.

Abstract: In a semiconductor device with a shared contact, a gate electrode is formed via a gate insulating film on a semiconductor substrate and a sidewall insulating film is formed on both side faces of the gate electrode. At least one of the surface parts of the semiconductor substrate adjacent to both sides of the gate electrode is removed beyond the lower part of the sidewall insulating film and to the underside of the gate electrode. Then, the gate insulating film exposed in the remove part is removed. An impurity-doped semiconductor layer is formed in the part where the semiconductor substrate and the gate insulating film have been removed.

Abstract: Some exemplary embodiments of a III-nitride power device including a HEMT with multiple interconnect metal layers and a solderable front metal structure using solder bars for external circuit connections have been disclosed. The solderable front metal structure may comprise a tri-metal such as TiNiAg, and may be configured to expose source and drain contacts of the HEMT as alternating elongated digits or bars. Additionally, a single package may integrate multiple such HEMTs wherein the front metal structures expose alternating interdigitated source and drain contacts, which may be advantageous for DC-DC power conversion circuit designs using III-nitride devices. By using solder bars for external circuit connections, lateral conduction is enabled, thereby advantageously reducing device Rdson.

Abstract: A high voltage durability III-nitride semiconductor device comprises a support substrate including a first silicon body, an insulator body over the first silicon body, and a second silicon body over the insulator body. The high voltage durability III-nitride semiconductor device further comprises a III-nitride semiconductor body characterized by a majority charge carrier conductivity type, formed over the second silicon body. The second silicon body has a conductivity type opposite the majority charge carrier conductivity type. In one embodiment, the high voltage durability III-nitride semiconductor device is a high electron mobility transistor (HEMT) comprising a support substrate including a <100> silicon layer, an insulator layer over the <100> silicon layer, and a P type conductivity <111> silicon layer over the insulator layer.

Abstract: In one embodiment a lateral HEMT has a first layer, the first layer including a semiconducting material, and a second layer, the second layer including a semiconducting material and being at least partially arranged on the first layer. The lateral HEMT further has a passivation layer and a drift region, the drift region including a lateral width wd. The lateral HEMT further has at least one field plate, the at least one field plate being arranged at least partially on the passivation layer in a region of the drift region and including a lateral width wf, wherein wf<wd.

Abstract: A field-effect semiconductor device such as a HEMT or MESFET is monolithically integrated with a Schottky diode for feedback, regeneration, or protection purposes. The field-effect semiconductor device includes a main semiconductor region having formed thereon a source, a drain, and a gate between the source and the drain. Also formed on the main semiconductor region, preferably between gate and drain, is a Schottky electrode electrically coupled to the source. The Schottky electrode provides a Schottky diode in combination with the main semiconductor region. A current flow is assured from Schottky electrode to drain without interruption by a depletion region expanding from the gate.

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: Normally-off semiconductor devices are provided. A Group III-nitride buffer layer is provided. A Group III-nitride barrier layer is provided on the Group III-nitride buffer layer. A non-conducting spacer layer is provided on the Group III-nitride barrier layer. The Group III-nitride barrier layer and the spacer layer are etched to form a trench. The trench extends through the barrier layer and exposes a portion of the buffer layer. A dielectric layer is formed on the spacer layer and in the trench and a gate electrode is formed on the dielectric layer. Related methods of forming semiconductor devices are also provided herein.

Abstract: A HEMT-type field-effect semiconductor device has a main semiconductor region comprising two layers of dissimilar materials such that a two-dimensional electron gas layer is generated along the heterojunction between the two layers. A source and a drain electrode are placed in spaced positions on a major surface of the main semiconductor region. Between these electrodes, a gate electrode is received in a recess in the major surface of the main semiconductor region via a p-type metal oxide semiconductor film whereby a depletion zone is normally created in the electron gas layer, with a minimum of turn-on resistance and gate leak current.

Abstract: A buffer layer formed of Inx1Aly1Gaz1N formed on a base, with an upper part of the buffer layer containing columnar polycrystalline including a grain boundary existing in a direction substantially perpendicular to a surface of the base. The number of grain boundaries in the lower part of the buffer layer is greater than that in the upper part, and a full width at half maximum of an X-ray rocking curve of the upper part is 300-3000 seconds, RMS of the surface of the buffer layer is 0.2 nm-6 nm, and the ratio of the grain boundary width of the crystal grain of the upper part in a direction parallel to the base surface to the formation thickness of the buffer layer is 0.5-1.5.

Abstract: A HEMT comprising a plurality of active semiconductor layers formed on a substrate. Source electrode, drain electrode, and gate are formed in electrical contact with the plurality of active layers. A spacer layer is formed on at least a portion of a surface of said plurality of active layers and covering the gate. A field plate is formed on the spacer layer and electrically connected to the source electrode, wherein the field plate reduces the peak operating electric field in the HEMT.

Abstract: Semiconductor structures include a trench formed proximate a substrate including a first semiconductor material. A crystalline material including a second semiconductor material lattice mismatched to the first semiconductor material is formed in the trench. Process embodiments include removing a portion of the dielectric layer to expose a side portion of the crystalline material and defining a gate thereover. Defects are reduced by using an aspect ratio trapping approach.

Abstract: A III-nitride semiconductor device which includes a barrier body between the gate electrode and the gate dielectric thereof.

Abstract: There is provided a hetero junction field effect transistor including: a first layer of a nitride based, group III-V compound semiconductor; a second layer of a nitride based, group III-V compound semiconductor containing a rare earth element, overlying the first layer; a pair of third layers of a nitride based, group III-V compound semiconductor, overlying the second layer, the third layers being spaced from each other; a gate electrode disposed between the third layers at least a region of the second layer; and a source electrode overlying one of the third layers and a drain electrode overlying an other of the third layers. A method of fabricating the hetero junction field effect transistor is also provided.

Abstract: A high electron mobility transistor includes a substrate, a buffer layer, a channel layer, a spacer layer, a schottky layer and a cap layer. The buffer layer is formed on the substrate. The channel layer is formed on the buffer layer, in which the channel layer comprises a superlattice structure formed with a plurality of indium gallium arsenide thin films alternately stacked with a plurality of indium arsenide thin films. The spacer layer is formed on the channel layer. The schottky layer is formed on the spacer layer. The cap layer is formed on the schottky layer.

Abstract: In an AlGaN channel transistor formed on a <100> orientation silicon wafer, a hole with walls slanted at 54 degrees is etched into the silicon to provide a <111> orientation substrate surface for forming the AlGaN channel transistor.

Abstract: A heterostructure having a heterojunction comprising: a diamond layer; and a boron aluminum nitride (B(x)Al(1-x)N) layer disposed in contact with a surface of the diamond layer, where x is between 0 and 1.

Abstract: Monolithic electronic devices are providing including a high bandgap layer. A first type of nitride device is provided on a first portion of the high bandgap layer, the first nitride device including first and second implanted regions respectively defining source and drain regions of the first type of nitride device. A second type of nitride device, different from the first type of nitride device, is provided on a second portion of the high bandgap layer, the second type of nitride device including an implanted highly conductive region. At least a portion of the implanted highly conductive region of the second type of nitride device is coplanar with at least a portion of both the first and second implanted regions of the first type of nitride device.

Abstract: Conductivity improvements in III-V semiconductor devices are described. A first improvement includes a barrier layer that is not coextensively planar with a channel layer. A second improvement includes an anneal of a metal/Si, Ge or SiliconGermanium/III-V stack to form a metal-Silicon, metal-Germanium or metal-SiliconGermanium layer over a Si and/or Germanium doped III-V layer. Then, removing the metal layer and forming a source/drain electrode on the metal-Silicon, metal-Germanium or metal-SiliconGermanium layer. A third improvement includes forming a layer of a Group IV and/or Group VI element over a III-V channel layer, and, annealing to dope the III-V channel layer with Group IV and/or Group VI species. A fourth improvement includes a passivation and/or dipole layer formed over an access region of a III-V device.

Abstract: A method for fabricating a transistor and the resulting transistor is disclosed. The method generally includes steps (A) to (E). Step (A) may form a high mobility layer. The high mobility layer is generally configured to carry a two-dimensional electron gas. Step (B) may form a planar layer on the high mobility layer. Step (C) may form a barrier layer on the planar layer. Step (D) may form a doped layer on the barrier layer. The doped layer is generally a low bandgap III-V semiconductor. Step (E) may form a gate in contact with the doped layer. The gate may be separated from both a source and a drain by corresponding ungated recess regions. The high mobility layer, the planar layer, the barrier layer, the doped layer, the source, the gate and the drain are generally configured as a pseudomorphic high electron mobility transistor.

Abstract: Semiconductor device including a metal carrier substrate. Above the carrier substrate a first semiconductor layer of Alx1Gay1Inz1N (x1+y1+z1=1, x1?0, y1?0, z1?0) is formed. A second semiconductor layer of Alx2Gay2Inz2N (x2+y2+z2=1, x2>x1, y2?0, z2?0) is arranged on the first semiconductor layer and a gate region is arranged on the second semiconductor layer. The semiconductor device furthermore includes a source region and a drain region, wherein one of these regions is electrically coupled to the metal carrier substrate and includes a conductive region extending through the first semiconductor layer.

Abstract: Embodiments of the invention relate to apparatus, system and method for use of a memory cell having improved power consumption characteristics, using a low-bandgap material quantum well structure together with a floating body cell.

Abstract: A compound semiconductor device is comprised of: a compound semiconductor layer including a first active layer and a second active layer forming a hetero junction with the first active layer so as to naturally generate a two-dimensional carrier gas channel in the first active layer along the hetero junction; a first electrode formed on the second active layer; a second electrode in ohmic contact with the first active layer and isolated from the first electrode; and a channel modifier for locally changing a part of the first active layer under the channel modifier into a normally-off state, the channel modifier being formed on the second active layer so as to enclose but be isolated from the first electrode and the second electrode.

Abstract: In one embodiment, a method for fabricating a III-Nitride transistor on a III-Nitride semiconductor body is disclosed. The method comprises etching dielectric trenches in a field dielectric overlying gate, source, and drain regions of the III-Nitride semiconductor body, and thereafter forming a gate dielectric over the gate, source and drain regions. The method further comprises forming a blanket diffusion barrier over the gate dielectric layer, and then removing respective portions of the blanket diffusion barrier from the source and drain regions. Thereafter, gate dielectric is removed from the source and drain regions to substantially expose the source and drain regions. Then, ohmic contacts are formed by depositing contact metal in the source and drain regions. The method results in highly conductive source/drain contacts that are particularly suitable for power transistors, for example, III-Nitride transistors, such as GaN transistors.

Abstract: Transistors are fabricated by forming a nitride-based semiconductor barrier layer on a nitride-based semiconductor channel layer and forming a protective layer on a gate region of the nitride-based semiconductor barrier layer. Patterned ohmic contact metal regions are formed on the barrier layer and annealed to provide first and second ohmic contacts. The annealing is carried out with the protective layer on the gate region. A gate contact is also formed on the gate region of the barrier layer. Transistors having protective layer in the gate region are also provided as are transistors having a barrier layer with a sheet resistance substantially the same as an as-grown sheet resistance of the barrier layer.

Abstract: Group III-nitride devices are described that include a stack of III-nitride layers, passivation layers, and conductive contacts. The stack includes a channel layer with a 2DEG channel, a barrier layer and a spacer layer. One passivation layer directly contacts a surface of the spacer layer on a side opposite to the channel layer and is an electrical insulator. The stack of III-nitride layers and the first passivation layer form a structure with a reverse side proximate to the first passivation layer and an obverse side proximate to the barrier layer. Another passivation layer is on the obverse side of the structure. Defected nucleation and stress management layers that form a buffer layer during the formation process can be partially or entirely removed.

Abstract: A quantum well device and a method for manufacturing the same are disclosed. In one aspect, the device includes a quantum well region overlying a substrate, a gate region overlying a portion of the quantum well region, a source and drain region adjacent to the gate region. The quantum well region includes a buffer structure overlying the substrate and including semiconductor material having a first band gap, a channel structure overlying the buffer structure including a semiconductor material having a second band gap, and a barrier layer overlying the channel structure and including an un-doped semiconductor material having a third band gap. The first and third band gap are wider than the second band gap. Each of the source and drain region is self-aligned to the gate region and includes a semiconductor material having a doped region and a fourth band gap wider than the second band gap.

Abstract: A transistor includes a protective layer having an opening extending therethrough on a substrate, and a gate electrode in the opening. First portions of the gate electrode laterally extend on surface portions of the protective layer outside the opening on opposite sides thereof, and second portions of the gate electrode are spaced apart from the protective layer and laterally extend beyond the first portions. Related devices are also discussed.

Abstract: A high electron mobility transistor (HEMT) is disclosed capable of performing as a pressure sensor. In one embodiment, the subject pressure sensor can be used for the detection of body fluid pressure. A piezoelectric, biocompatible film can be used to provide a pressure sensing functionalized gate surface for the HEMT. Embodiments of the disclosed sensor can be integrated with a wireless transmitter for constant pressure monitoring.

Abstract: A semiconductor structure is described. The structure includes a transistor formed in a semiconductor substrate, the semiconductor substrate having a semiconductor-on-insulator (SOI) layer; a channel associated with the transistor and formed on a first portion of the SOI layer; and a source/drain region associated with the transistor and formed in a second portion of the SOI layer and in a recess at each end of the channel, where the second portion of the SOI layer is substantially thicker than the first portion of the SOI layer. A method of fabricating the semiconductor structure is also described.

Abstract: According to one embodiment, a III-nitride transistor includes a conduction channel formed between first and second III-nitride bodies, the conduction channel including a two-dimensional electron gas. The transistor also includes at least one gate dielectric layer having a charge confined within to cause an interrupted region of the conduction channel and a gate electrode operable to restore the interrupted region of the conduction channel. The transistor can be an enhancement mode transistor. In one embodiment, the gate dielectric layer is a silicon nitride layer. In another embodiment, the at least one gate dielectric layer is a silicon oxide layer. The charge can be ion implanted into the at least one gate dielectric layer. The at least one gate dielectric layer can also be grown with the charge.

Abstract: In one embodiment, a floating body field-effect transistor includes a pair of source/drain regions having a floating body channel region received therebetween. The source/drain regions and the floating body channel region are received over an insulator. A gate electrode is proximate the floating body channel region. A gate dielectric is received between the gate electrode and the floating body channel region. The floating body channel region has a semiconductor SixGe(1-x)-comprising region. The floating body channel region has a semiconductor silicon-comprising region received between the semiconductor SixGe(1-x)-comprising region and the gate dielectric. The semiconductor SixGe(1-x)-comprising region has greater quantity of Ge than any quantity of Ge within the semiconductor silicon-comprising region. Other embodiments are contemplated, including methods of forming floating body field-effect transistors.

Abstract: Embodiments of the present invention provide binding molecule-functionalized high electron mobility transistors (HEMTs) that can be used to detect toxins, pathogens and other biological materials. In a specific embodiment, an antibody-functionalized HEMT can be used to detect botulinum toxin. The antibody can be anchored to a gold-layered gate area of the HEMT through immobilized thioglycolic acid. Embodiments of the subject detectors can be used in field-deployable electronic biological applications based on AlGaN/GaN HEMTs.

Abstract: A multiple field plate transistor includes an active region, with a source, a drain, and a gate. A first spacer layer is over the active region between the source and the gate and a second spacer layer over the active region between the drain and the gate. A first field plate on the first spacer layer is connected to the gate. A second field plate on the second spacer layer is connected to the gate. A third spacer layer is on the first spacer layer, the second spacer layer, the first field plate, the gate, and the second field plate, with a third field plate on the third spacer layer and connected to the source. The transistor exhibits a blocking voltage of at least 600 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 5.0 m?-cm2, of at least 600 Volts while supporting a current of at least 3 Amps with an on resistance of no more than 5.3 m?-cm2, of at least 900 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 6.

Abstract: An improved high breakdown voltage semiconductor device and method for manufacturing is provided. The device has a substrate and a AlaGa1-aN layer on the substrate wherein 0.1?a?1.00. A GaN layer is on the AlaGa1-aN layer. An In1-bGabN/GaN channel layer is on the GaN layer wherein 0.1?b?1.00. A AlcIndGa1-c-dN spacer layer is on the In1-bGabN/GaN layer wherein 0.1?c?1.00 and 0.0?d?0.99. A AleIn1-eN nested superlattice barrier layer is on the AlcIndGa1-c-dN spacer layer wherein 0.10?e?0.99. A AlfIngGa1-f-gN leakage suppression layer is on the AleIn1-eN barrier layer wherein 0.1?f?0.99 and 0.1?g?0.99 wherein the leakage suppression layer decreases leakage current and increases breakdown voltage during high voltage operation. A superstructure, preferably with metallic electrodes, is on the AlfIngGa1-f-gN leakage suppression layer.

Abstract: Semiconductor transistor devices and related fabrication methods are provided. An exemplary transistor device includes a layer of semiconductor material having a channel region defined therein and a gate structure overlying the channel region. Recesses are formed in the layer of semiconductor material adjacent to the channel region, such that the recesses extend asymmetrically toward the channel region. The transistor device also includes stress-inducing semiconductor material formed in the recesses. The asymmetric profile of the stress-inducing semiconductor material enhances carrier mobility in a manner that does not exacerbate the short channel effect.

Abstract: It is an object of the present invention to provide a nitride semiconductor device with low parasitic resistance by lowering barrier height to reduce contact resistance at an interface of semiconductor and metal. The nitride semiconductor device includes a GaN layer, a device isolation layer, an ohmic electrode, an n-type Al0.25Ga0.75N layer, a sapphire substrate, and a buffer layer. A main surface of the n-type Al0.25Ga0.75N layer is on (0 0 0 1) plane as a main surface, and concaves are arranged in a checkerboard pattern on the surface. The ohmic electrode contacts the sides of the concaves of the n-type Al0.25Ga0.75N layer, and the sides of the concaves are on non-polar surfaces such as (1 1 ?2 0) plane or (1 ?1 0 0) plane.