Abstract: In an ultra high voltage lateral GaN structure having a 2DEG region extending between two terminals, an isolation region is provided between the two terminals to provide for reversible snapback.

Abstract: The present invention concerns a method of forming a chalcogenide thin film for a phase-change memory. In the method of forming a chalcogenide thin film according to the present invention, a substrate with a pattern formed is loaded into a reactor, and a source gas is supplied onto the substrate. Here, the source gas includes at least one source gas selected from germanium (Ge) source gas, gallium (Ga) source gas, indium (In) source gas, selenium (Se) source gas, antimony (Sb) source gas, tellurium (Te) source gas, tin (Sn) source gas, silver (Ag) source gas, and sulfur (S) source gas. A first purge gas is supplied onto the substrate in order to purge the source gas supplied onto the substrate, a reaction gas for reducing the source gas is then supplied onto the substrate, and a second purge gas is supplied onto the substrate in order to purge the reaction gas supplied onto the substrate.

Abstract: This composite semiconductor device has a normally-on first field effect transistor and a normally-off second field effect transistor connected in series between first and second terminals, gates of the first and second field effect transistors being connected to second and third terminals, respectively, and N diodes being connected in series in a forward direction between a drain and a source of the second field effect transistor. Therefore, a drain-source voltage (Vds) of the second field effect transistor can be restricted to a voltage not higher than a withstand voltage of the second field effect transistor.

Abstract: A nitride semiconductor substrate is featured in comprising: a GaN semiconductor layer grown on a base layer, which has a substantially triangular cross-section along the thickness direction thereof, a periodic stripe shapes, and uneven surfaces arranged on the stripes inclined surfaces; and an overgrown layer composed of AlGaN or InAlGaN on the GaN semiconductor layer.

Abstract: A light emitting device is disclosed. The light emitting device includes a first conductive type semiconductor layer, an active layer disposed on the first conductive type semiconductor layer, a tunnel junction layer comprising a second conductive type nitride semiconductor layer and a first conductive type nitride semiconductor layer disposed on the active layer, wherein the first conductive type nitride semiconductor layer and the second conductive type nitride semiconductor layer are PN junctioned, a first electrode disposed on the first conductive type semiconductor layer, and a second electrode disposed on the first conductive type nitride semiconductor layer, wherein a portion of the second electrode is in schottky contact with the second conductive type nitride semiconductor layer through the first conductive type nitride semiconductor layer.

Abstract: Semiconductor device stacks and devices made there from having Ge-rich device layers. A Ge-rich device layer is disposed above a substrate, with a p-type doped Ge etch suppression layer (e.g., p-type SiGe) disposed there between to suppress etch of the Ge-rich device layer during removal of a sacrificial semiconductor layer richer in Si than the device layer. Rates of dissolution of Ge in wet etchants, such as aqueous hydroxide chemistries, may be dramatically decreased with the introduction of a buried p-type doped semiconductor layer into a semiconductor film stack, improving selectivity of etchant to the Ge-rich device layers.

Abstract: A method for fabricating an edge termination, which can be used in conjunction with GaN-based materials, includes providing a substrate of a first conductivity type. The substrate has a first surface and a second surface. The method also includes forming a first GaN epitaxial layer of the first conductivity type coupled to the first surface of the substrate and forming a second GaN epitaxial layer of a second conductivity type opposite to the first conductivity type. The second GaN epitaxial layer is coupled to the first GaN epitaxial layer. The substrate, the first GaN epitaxial layer and the second GaN epitaxial layer can be referred to as an epitaxial structure.

Abstract: An object of the present invention is to address the problems described herein and to provide a III-nitride semiconductor epitaxial substrate, a III-nitride semiconductor element, and a III-nitride semiconductor freestanding substrate, which have good crystallinity, not only with AlGaN, GaN, or GaInN, the growth temperature of which is at or below 1050° C., but also with AlxGa1-xN, the growth temperature of which is high and which has a high Al composition, as well as a III-nitride semiconductor growth substrate for fabricating these and a method for efficiently fabricating these. The invention is characterized by being equipped with: a crystal growth substrate, at least the surface portion of which substrate includes a III-nitride semiconductor containing Al; and a single metallic layer formed on the surface portion, the single metallic layer being made from Zr or Hf.

Abstract: To grow a gallium nitride crystal, a seed-crystal substrate is first immersed in a melt mixture containing gallium and sodium. Then, a gallium nitride crystal is grown on the seed-crystal substrate under heating the melt mixture in a pressurized atmosphere containing nitrogen gas and not containing oxygen. At this time, the gallium nitride crystal is grown on the seed-crystal substrate under a first stirring condition of stirring the melt mixture, the first stirring condition being set for providing a rough growth surface, and the gallium nitride crystal is subsequently grown on the seed-crystal substrate under a second stirring condition of stirring the melt mixture, the second stirring condition being set for providing a smooth growth surface.

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: The present invention discloses methods to create higher quality group III-nitride wafers that then generate improvements in the crystalline properties of ingots produced by ammonothermal growth from an initial defective seed. By obtaining future seeds from carefully chosen regions of an ingot produced on a bowed seed crystal, future ingot crystalline properties can be improved. Specifically, the future seeds are optimized if chosen from an area of relieved stress on a cracked ingot or from a carefully chosen N-polar compressed area. When the seeds are sliced out, miscut of 3-10° helps to improve structural quality of successive growth. Additionally a method is proposed to improve crystal quality by using the ammonothermal method to produce a series of ingots, each using a specifically oriented seed from the previous ingot. When employed, these methods enhance the quality of Group III nitride wafers and thus improve the efficiency of any subsequent device.

Abstract: Embodiments relate to growing an epitaxy gallium-nitride (GaN) layer on a porous silicon (Si) substrate. The porous Si substrate has a larger surface area compared to non-porous Si substrate to distribute and accommodate stress caused by materials deposited on the substrate. An interface adjustment layer (e.g., transition metal silicide layer) is formed on the porous silicon substrate to promote growth of a buffer layer. A buffer layer formed for GaN layer may then be formed on the silicon substrate. A seed-layer for epitaxial growth of GaN layer is then formed on the buffer layer.

Abstract: The present disclosure relates to a nitride electronic device and a method for manufacturing the same, and particularly, to a nitride electronic device and a method for manufacturing the same that can implement various types of nitride integrated structures on the same substrate through a regrowth technology (epitaxially lateral over-growth: ELOG) of a semi-insulating gallium nitride (GaN) layer used in a III-nitride semiconductor electronic device including Group III elements such as gallium (Ga), aluminum (Al) and indium (In) and nitrogen.

Abstract: Provided is a method of fabricating a semiconductor device. The method includes providing a silicon substrate having opposite first and second sides. At least one of the first and second sides includes a silicon (111) surface. The method includes forming a high coefficient-of-thermal-expansion (CTE) layer on the first side of the silicon substrate. The high CTE layer has a CTE greater than the CTE of silicon. The method includes forming a buffer layer over the second side of the silicon substrate. The buffer layer has a CTE greater than the CTE of silicon. The method includes forming a III-V family layer over the buffer layer. The III-V family layer has a CTE greater than the CTE of the buffer layer.

Abstract: Techniques for crack-free growth of GaN, and related, films on larger-size substrates via spatially confined epitaxy are described.

Abstract: A semiconductor structure includes a GaN substrate having a first surface and a second surface opposing the first surface. The GaN substrate is characterized by a first conductivity type and a first dopant concentration. The semiconductor structure also includes a first GaN epitaxial layer of the first conductivity type coupled to the second surface of the GaN substrate and a second GaN epitaxial layer of a second conductivity type coupled to the first GaN epitaxial layer. The second GaN epitaxial layer includes an active device region, a first junction termination region characterized by an implantation region having a first implantation profile, and a second junction termination region characterized by an implantation region having a second implantation profile.

Abstract: The nitride semiconductor material according to the present invention includes a group III nitride semiconductor and a group IV nitride formed on the group III nitride semiconductor, where an interface between the group III nitride semiconductor and the group IV nitride has a regular atomic arrangement. Moreover, an arrangement of nitrogen atoms of the group IV nitride in the interface and an arrangement of group III atoms of the group III nitride semiconductor in the interface may be substantially identical.

Abstract: Provided is a method of manufacturing III-nitride crystal having a major surface of plane orientation other than {0001}, designated by choice, the III-nitride crystal manufacturing method including: a step of slicing III-nitride bulk crystal through a plurality of planes defining a predetermined slice thickness in the direction of the designated plane orientation, to produce a plurality of III-nitride crystal substrates having a major surface of the designated plane orientation; a step of disposing the substrates adjoining each other sideways in a manner such that the major surfaces of the substrates parallel each other and such that any difference in slice thickness between two adjoining III-nitride crystal substrates is not greater than 0.1 mm; and a step of growing III-nitride crystal onto the major surfaces of the substrates.

Abstract: Solid state lighting devices and associated methods of manufacturing are disclosed herein. In one embodiment, a solid state light device includes a light emitting diode with an N-type gallium nitride (GaN) material, a P-type GaN material spaced apart from the N-type GaN material, and an indium gallium nitride (InGaN) material directly between the N-type GaN material and the P-type GaN material. At least one of the N-type GaN, InGaN, and P-type GaN materials has a non-planar surface.

Abstract: A semiconductor arrangement is provided that includes one or more substrate structures. One or more nitride-based material structures are used in fabricating nitride-based devices. One or more intermediary layers are interposed between the one or more substrate structures and the one or more nitride-based material structures. The one or more intermediary layers support the lattice mismatch and thermal expansion coefficients between the one or more nitride-based material structure and the one or more substrate structures. Several new electronic devices based on this arrangement are described.

Abstract: A semiconductor structure includes a GaN substrate with a first surface and a second surface. The GaN substrate is characterized by a first conductivity type and a first dopant concentration. A first electrode is electrically coupled to the second surface of the GaN substrate. The semiconductor structure further includes a first GaN epitaxial layer of the first conductivity type coupled to the first surface of the GaN substrate and a second GaN layer of a second conductivity type coupled to the first GaN epitaxial layer. The first GaN epitaxial layer comprises a channel region. The second GaN epitaxial layer comprises a gate region and an edge termination structure. A second electrode coupled to the gate region and a third electrode coupled to the channel region are both disposed within the edge termination structure.

Abstract: A method of manufacturing a heterostructure device is provided that includes implantation of ions into a portion of a surface of a multi-layer structure. Iodine ions are implanted between a first region and a second region to form a third region. A charge is depleted from the two dimensional electron gas (2DEG) channel in the third region to form a reversibly electrically non-conductive pathway from the first region to the second region. On applying a voltage potential to a gate electrode proximate to the third region allows electrical current to flow from the first region to the second region.

Abstract: A semiconductor structure is bonded directly to a diamond substrate by Van der Waal forces. The diamond substrate is formed by polishing a surface of diamond to a first degree of smoothness; forming a material, such as diamond, BeO, GaN, MgO, or SiO2 or other oxides, over the polished surface to provide an intermediate structure; and re-polishing the material formed on the intermediate structure to a second degree of smoothness smoother than the first degree of smoothness. The diamond is bonded to the semiconductor structure, such as GaN, by providing a structure having bottom surfaces of a semiconductor on an underlying material; forming grooves through the semiconductor and into the underlying material; separating semiconductor along the grooves into a plurality of separate semiconductor structures; removing the separated semiconductor structures from the underlying material; and contacting the bottom surface of at least one of the separated semiconductor structures to the diamond substrate.

Abstract: A method is provided for fabricating three-dimensional gallium nitride (GaN) pillar structures with planar surfaces. After providing a substrate, the method grows a GaN film overlying a top surface of the substrate and forms cavities in a top surface of the GaN film. The cavities are formed using a laser ablation, ion implantation, sand blasting, or dry etching process. The cavities in the GaN film top surface are then wet etched, forming planar sidewalls extending into the GaN film. More explicitly, the cavities are formed into a c-plane GaN film top surface, and the planar sidewalls are formed perpendicular to a c-plane, in the m-plane or a-plane family.

Abstract: An integrated circuit is provided, the integrated circuit including: a carrier including at least one electronic component and at least one contact area disposed on a first side of the carrier, wherein the at least one electronic component is electrically connected to the at least one contact area; an inorganic material layer wafer bonded to the first side of the carrier, wherein the carrier has a first coefficient of thermal expansion, and wherein the inorganic material layer has a second coefficient of thermal expansion, wherein the second coefficient of thermal expansion has a difference of less than 100% compared with the first coefficient of thermal expansion; and at least one contact via formed through the inorganic material layer, wherein the at least one contact via contacts the at least one contact area.

Abstract: A method for making an epitaxial structure includes: (a) providing a sacrificial layer on a temporary substrate, the sacrificial layer being made of gallium oxide; and (b) growing epitaxially an epitaxial layer unit over the sacrificial layer.

Abstract: Composite substrates are produced that include a strained III-nitride material seed layer on a support substrate. Methods of producing the composite substrate include developing a desired lattice strain in the III-nitride material to produce a lattice parameter substantially matching a lattice parameter of a device structure to be formed on the composite substrate. The III-nitride material may be formed with a Ga polarity or an N polarity. The desired lattice strain may be developed by forming a buffer layer between the III-nitride material and a growth substrate, implanting a dopant in the III-nitride material to modify its lattice parameter, or forming the III-nitride material with a coefficient of thermal expansion (CTE) on a growth substrate with a different CTE.

Abstract: The present invention provides a method for producing a Group III nitride semiconductor. The method includes forming a groove in a surface of a growth substrate through etching; forming a buffer film on the groove-formed surface of the growth substrate through sputtering; heating, in an atmosphere containing hydrogen and ammonia, the substrate to a temperature at which a Group III nitride semiconductor of interest is grown; and epitaxially growing the Group III nitride semiconductor on side surfaces of the groove at the growth temperature. The thickness of the buffer film or the growth temperature is regulated so that the Group III nitride semiconductor is grown primarily on the side surfaces of the groove in a direction parallel to the main surface of the growth substrate.

Abstract: A HEMT includes a silicon substrate, an unintentionally doped gallium nitride (UID GaN) layer over the silicon substrate, a donor-supply layer over the UID GaN layer, a gate structure, a drain, and a source over the donor-supply layer, and a passivation material layer having one or more buried portions contacting or almost contacting the UID GaN layer. A carrier channel layer at the interface of the donor-supply layer and the UID GaN layer has patches of non-conduction in a drift region between the gate and the drain. A method for making the HEMT is also provided.

Abstract: An integrated circuit structure includes a substrate; a channel layer over the substrate, wherein the channel layer is formed of a first III-V compound semiconductor material; a highly doped semiconductor layer over the channel layer; a gate dielectric penetrating through and contacting a sidewall of the highly doped semiconductor layer; and a gate electrode on a bottom portion of the gate dielectric. The gate dielectric includes a sidewall portion on a sidewall of the gate electrode.

Abstract: There are provided a group III nitride semiconductor light emitting device which is constituted of a substrate, an intermediate layer formed thereon having a favorable level of orientation properties, and a group III nitride semiconductor formed thereon having a favorable level of crystallinity, and having excellent levels of light emitting properties and productivity; a production method thereof; and a lamp, the group III nitride semiconductor light emitting device configured so that at least an intermediate layer 12 composed of a group III nitride compound is laminated on a substrate 11, and an n-type semiconductor layer 14 having a base layer 14a, a light emitting layer 15 and a p-type semiconductor layer 16 are sequentially laminated on the intermediate layer 12, wherein when components are separated, based on a peak separation technique using an X-ray rocking curve of the intermediate layer 12, into a broad component having the full width at half maximum of 720 arcsec or more and a narrow component,

Abstract: An electrical device includes a blocking layer disposed on top of a substrate layer, wherein the blocking layer and the substrate layer each are wide bandgap semiconductors, and the blocking layer and the substrate layer form a buried junction in the electrical device. The device comprises a termination feature disposed at a surface of the blocking layer and a filled trench disposed proximate to the termination feature. The filled trench extends through the blocking layer to reach the substrate layer and is configured to direct an electrical potential associated with the buried junction toward the termination feature disposed near the surface of the blocking layer to terminate the buried junction.

Abstract: An embodiment of a semiconductor device includes a gallium nitride (GaN) substrate having a first surface and a second surface. The second surface is substantially opposite the first surface, at least one device layer is coupled to the first surface, and a backside metal is coupled to the second surface. A top metal stack is coupled to the at least one device layer. The top metal stack includes a contact metal coupled to a surface of the at least one device layer, a protection layer coupled to the contact metal, a diffusion barrier coupled to the protection layer, and a pad metal coupled to the diffusion barrier. The semiconductor device is configured to conduct electricity between the top metal stack and the backside metal.

Abstract: A chip package is provided, the chip package including: a carrier including at least one cavity; a chip disposed at least partially within the at least one cavity; at least one intermediate layer disposed over at least one side wall of the chip; wherein the at least one intermediate layer is configured to thermally conduct heat from the chip to the carrier.

Abstract: A dimpled substrate and method of making including a substrate of high thermal conductivity having a first main surface and a second main surface opposite the first main surface. Active epitaxial layers are formed on the first main surface of the substrate. Dimples are formed as extending from the second main surface into the substrate toward the first main surface. An electrical contact of low resistance material is disposed on the second main surface and within the dimples. A back contact of low resistance and low loss is thus provided while maintaining the substrate as an effective heat sink.

Abstract: A compound semiconductor integrated circuit is provided, comprising a substrate, at least one compound semiconductor electronic device, a first metal layer, a protection layer, a plurality of second metal layers, and at least one dielectric layer. The first metal layer contains Au but does not contain Cu, and is at least partly electrically connected to the compound semiconductor electronic device. The protection layer covers the compound semiconductor electronic device and at least part of the first metal layer. Each of the plurality of second metal layers contains at least a Cu layer, and at least one of the plurality of second metal layers is partly electrically connected to the first metal layer described above. The at least one dielectric layer separates each pair of adjacent second metal layers. The second metal layers are used to form passive electronic components.

Abstract: A surface of a sapphire (0001) substrate is processed so as to have recesses and protrusions so that protrusion tops are made flat and have a given plan-view pattern. An initial-stage AlN layer is epitaxially grown on the surface of the sapphire (0001) substrate so that new recesses are formed over the recesses, by performing C axis orientation control so that a C+ axis oriented AlN layer grows on flat surfaces of the protrusion tops, excluding edges. A first ELO layer including an AlN (0001) layer is epitaxially grown on the initial-stage AlN layer by an epitaxial lateral overgrowth method, and stops growing before a recess upper region above the new recesses is completely covered with the first ELO layer that is laterally grown from a protrusion upper surface of the initial-stage AlN layer. A second ELO layer including an AlxGa1-xN (0001) layer (1>x>0) is epitaxially grown on the first ELO layer by an epitaxial lateral overgrowth method.

Abstract: A method for fabricating an electronic device includes providing an engineered substrate structure comprising a III-nitride seed layer, forming GaN-based functional layers coupled to the III-nitride seed layer, and forming a first electrode structure electrically coupled to at least a portion of the GaN-based functional layers. The method also includes joining a carrier substrate opposing the GaN-based functional layers and removing at least a portion of the engineered substrate structure. The method further includes forming a second electrode structure electrically coupled to at least another portion of the GaN-based functional layers and removing the carrier substrate.

Abstract: A high electron mobility transistor (HEMT) 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 source feature and a drain feature are in contact with the second III-V compound layer. A n-type doped region underlies each source feature and drain feature in the second III-V compound layer. A p-type doped region underlies each n-type doped region in the first III-V compound layer. A gate electrode is disposed over a portion of the second III-V compound layer between the source feature and the drain feature.

Abstract: There is provided a method of forming a nitride semiconductor layer, including the steps of firstly providing a substrate on which a patterned epitaxy layer with a pier structure is formed. A protective layer is then formed on the patterned epitaxy layer, exposing a top surface of the pier structure. Next, a nitride semiconductor layer is formed over the patterned epitaxy layer connected to the nitride semiconductor layer through the pier structure, wherein the nitride semiconductor layer, the pier structure, and the patterned epitaxy layer together form a space exposing a bottom surface of the nitride semiconductor layer. Thereafter, a weakening process is performed to remove a portion of the bottom surface of the nitride semiconductor layer and to weaken a connection point between the top surface of the pier structure and the nitride semiconductor layer. Finally, the substrate is separated from the nitride semiconductor layer through the connection point.

Abstract: A MOSFET which is a semiconductor device capable of achieving a stable reverse breakdown voltage and reduced on-resistance includes a SiC wafer of an n conductivity type, a plurality of p bodies of a p conductivity type formed to include a first main surface of the SiC wafer, and n+ source regions of the n conductivity type formed in regions surrounded by the plurality of p bodies, respectively, when viewed two-dimensionally. Each of the p bodies has a circular shape when viewed two-dimensionally, and each of the n+ source regions is arranged concentrically with each of the p bodies and has a circular shape when viewed two-dimensionally. Each of the plurality of p bodies is arranged to be positioned at a vertex of a regular hexagon when viewed two-dimensionally.

Abstract: A nitride based semiconductor package includes a nitride based semiconductor device, a package substrate, and a bonding substrate. The semiconductor device includes, on a surface thereof, a first electrode pattern having a source electrode, a drain electrode and a gate electrode. The bonding substrate includes, on a first surface thereof, a second electrode pattern corresponding to the first electrode pattern, and at least one first groove pattern. The first groove pattern exposes the second electrode pattern. The first electrode pattern is received in the at least one first groove pattern. The second electrode pattern is bonded to the first electrode pattern received in the at least one first groove pattern. A second surface of the bonding substrate is bonded to the package substrate.

Abstract: A method for growing reduced defect density planar gallium nitride (GaN) films is disclosed. The method includes the steps of (a) growing at least one silicon nitride (SiNx) nanomask layer over a GaN template, and (b) growing a thickness of a GaN film on top of the SiNx nanomask layer.

Abstract: Embodiments relate to growing an epitaxy gallium-nitride (GaN) layer on a porous silicon (Si) substrate. The porous Si substrate has a larger surface area compared to non-porous Si substrate to distribute and accommodate stress caused by materials deposited on the substrate. An interface adjustment layer (e.g., transition metal silicide layer) is formed on the porous silicon substrate to promote growth of a buffer layer. A buffer layer formed for GaN layer may then be formed on the silicon substrate. A seed-layer for epitaxial growth of GaN layer is then formed on the buffer layer.

Abstract: Methods of fabricating semiconductor structures include forming a plurality of openings extending through a semiconductor material and at least partially through a metal material and deforming the metal material to relax a remaining portion of the semiconductor material. The metal material may be deformed by exposing the metal material to a temperature sufficient to alter (i.e., increase) its ductility. The metal material may be formed from one or more of hafnium, zirconium, yttrium, and a metallic glass. Another semiconductor material may be deposited over the remaining portions of the semiconductor material, and a portion of the metal material may be removed from between each of the remaining portions of the semiconductor material. Semiconductor structures may be formed using such methods.

Abstract: In a method for making a GaN article, an epitaxial nitride layer is deposited on a single-crystal substrate. A 3D nucleation GaN layer is grown on the epitaxial nitride layer by HVPE under a substantially 3D growth mode. A GaN transitional layer is grown on the 3D nucleation layer by HVPE under a condition that changes the growth mode from the substantially 3D growth mode to a substantially 2D growth mode. A bulk GaN layer is grown on the transitional layer by HVPE under the substantially 2D growth mode. A polycrystalline GaN layer is grown on the bulk GaN layer to form a GaN/substrate bi-layer. The GaN/substrate bi-layer may be cooled from the growth temperature to an ambient temperature, wherein GaN material cracks laterally and separates from the substrate, forming a free-standing article.

Abstract: A method for fabricating a vertical gallium nitride (GaN) power device can include providing a GaN substrate with a top surface and a bottom surface, forming a device layer coupled to the top surface of the GaN substrate, and forming a metal contact on a top surface of the vertical GaN power device. The method can further include forming a backside metal by forming an adhesion layer coupled to the bottom surface of the GaN substrate, forming a diffusion barrier coupled to the adhesion layer, and forming a protection layer coupled to the diffusion barrier. The vertical GaN power device can be configured to conduct electricity between the metal contact and the backside metal.

Abstract: Thin flat crack-free freestanding nitride layers are fabricated by laser patterning of the interface and/or opposing surface of the nitride layer. The nitride layer is substantially flat once removed from the non-native substrate. The thin flat crack free nitride layers are between 3 and 250 microns thick and can have areas greater than 1 cm2.

Abstract: A semiconductor structure having mesa structure comprising: a lower semiconductor layer; an upper semiconductor layer having a higher band gap than, and in direct contact with, the lower semiconductor layer to form a two-dimension electron gas (2DEG) region between the upper semiconductor layer. The 2DEG region has outer edges terminating at sidewalls of the mesa. An additional electron donor layer has a band gap higher than the band gap of the lower layer disposed on sidewall portions of the mesa structure and on the region of the 2DEG region terminating at sidewalls of the mesa. An ohmic contact material is disposed on the electron donor layer. In effect, a sideway HEMT is formed with the electron donor layer, the 2DEG region and the ohmic contact material increasing the concentration of electrons (i.e., lowering ohmic contact resistance) all along the contact between the lower semiconductor layer and the electron donor layer.

Abstract: A Schottky diode includes a first nitride-based semiconductor layer disposed atop a substrate. A second nitride-based semiconductor layer is disposed atop a portion of the first nitride-based semiconductor layer. The second layer has a doping concentration lower than that of the first layer. A first Schottky contact metal layer having a first metal work function is disposed on a top planar surface of the second layer, forming a first Schottky junction. A second Schottky contact metal layer having a second metal work function is disposed atop of and laterally surrounding the first Schottky contact metal layer, the metal work function of the second metal layer is higher than that of the first metal layer. A metal layer disposed on first and second planar surfaces forms an ohmic contact with the first nitride-based semiconductor layer.