Abstract: A high electron mobility field effect transistor (HEMT) having a substrate, a channel layer on the substrate and a barrier layer on the channel layer includes a stress inducing layer on the barrier layer, the stress inducing layer varying the piezo-electric effect in the barrier layer in a drift region between a gate and a drain. A two dimensional electron gas (2DEG) has a non-uniform lateral distribution in the drift region between the gate and the drain.

Abstract: A monolithically integrated device includes a substrate, a first set of Group III nitride epitaxial layers grown for a first HFET on a first region of the substrate, and a second set of Group III nitride epitaxial layers for a second HFET grown on a second region of the substrate.

Abstract: The interface resistance between the source/drain and gate of an HFET may be significantly reduced by engineering the bandgap of the 2DEG outside a gate region such that the charge density is substantially increased. The resistance may be further reduced by using an n+GaN Cap layer over the channel layer and barrier layer such that a horizontal surface of the barrier layer beyond the gate region is covered by the n+GaN Cap layer. This technique is applicable to depletion and enhancement mode HFETs.

Abstract: A method of making a stepped field gate for an FET including forming a first set of layers having a passivation layer on a barrier layer of the FET and a first etch stop layer over the first passivation layer, forming additional sets of layers having alternating passivation layer and etch stop layers, successively removing portions of each set of layers using lithography and reactive ion etching to form stepped passivation layers and a gate foot, applying a mask having an opening defining an extent of a stepped field-plate gate, and forming the stepped field plate gate and the gate foot by plating through the opening in the mask.

Abstract: A system for forming self-aligned contacts includes electroplating a first metal contact onto a Group III-V semiconductor substrate, the first metal contact having a greater height than width and having a straight sidewall profile, etching back the semiconductor substrate down to a base layer to expose an emitter semiconductor layer under the first metal contact, conformally depositing a dielectric layer on a vertical side of the first metal contact, a vertical side of the emitter semiconductor layer and on the base layer, anisotropically etching the dielectric layer off of the semiconductor substrate to form a dielectric sidewall spacer on the vertical side of the first metal contact and providing a second metal contact immediately adjacent the dielectric sidewall spacer.

Abstract: A method of making a stepped field gate for an FET including forming a first passivation layer on a barrier layer, defining a first field plate by using electron beam (EB) lithography and by depositing a first negative EB resist, forming a second passivation layer over first negative EB resist and the first passivation layer, planarizing the first negative EB resist and the second passivation layer, defining a second field plate by using EB lithography and by depositing a second negative EB resist connected to the first negative EB resist, forming a third passivation layer over second negative EB resist and the second passivation layer, planarizing the second negative EB resist and the third passivation layer, removing the first and second negative EB resist, and forming a stepped field gate by using lithography and plating in a void left by the removed first and second negative EB resist.

Abstract: In a silver-plated product wherein a surface layer of silver is formed on the surface of a base material or on the surface of an underlying layer formed on the base material, the surface layer of silver is formed by electroplating in a silver plating bath which contains 1 to 15 mg/L of selenium and wherein a mass ratio of silver to free cyanogen is in the range of from 0.9 to 1.8, and thereafter, an aging treatment is carried out to produce a silver-plated product wherein an area fraction in {200} orientation of the surface layer is 15% or more.

Abstract: There is provided a silver-plated product which has a good bendability and which can restrain the rise of the contact resistance thereof even if it is used in a high-temperature environment, and a method for producing the same. In a silver-plated product wherein a surface layer of silver is formed on the surface of a base material of copper or a copper alloy, or on the surface of an underlying layer of copper or a copper alloy formed on the base material, the percentage of an X-ray diffraction intensity on {200} plane of the surface layer with respect to the sum of X-ray diffraction intensities on {111}, {200}, {220} and {311} planes of the surface layer is 40% or more.

Abstract: A semiconductor device comprises one or more transistors and two or more layers of dielectric material encapsulating a front side of said one or more transistors. The gate of each of said one or more transistors is located within a cavity, or air-box, in at least one of the dielectric layers, so that the gate terminal is physically separated from said dielectric material. Such an arrangement may reduce parasitic capacitance. In another arrangement, a semiconductor device comprises one or more gallium nitride high electron mobility transistors and one or more dielectric layers encapsulating a front side of said one or more transistors, wherein the gate terminal of each of said one or more transistors is located within a cavity in at least one of the one or more dielectric layers, separated from said dielectric material.

Abstract: A method of forming a slanted field plate including forming epitaxy for a FET on a substrate, forming a wall near a drain of the FET, the wall comprising a first negative tone electron-beam resist (NTEBR), depositing a dielectric over the epitaxy and the wall, the wall causing the dielectric to have a step near the drain of the FET, depositing a second NTEBR over the dielectric, wherein surface tension causes the deposited second NTEBR to have a slanted top surface between the step and a source of the FET, etching anisotropically vertically the second NTEBR and the dielectric to remove the second NTEBR and to transfer a shape of the slanted top surface to the dielectric, and forming a gatehead comprising metal on the dielectric between the step and the source of the FET, wherein the gatehead forms a slanted field plate.

Abstract: There is provided a silver-plated product wherein a silver plating film having a thickness of not greater than 10 micrometers is formed on a base material of copper or a copper alloy and wherein the surface of the silver plating film has an arithmetic average roughness Ra of not greater than 0.1 micrometers, and the silver plating film has a {111} orientation ratio of not less than 35%.

Abstract: Monolithic integration of high-frequency GaN-HEMTs and GaN-Schottky diodes. The integrated HEMTs/Schottky diodes are realized using an epitaxial structure and a fabrication process which reduces fabrication cost. Since the disclosed process preferably uses self-aligned technology, both devices show extremely high-frequency performance by minimizing device parasitic resistances and capacitances. Furthermore, since the Schottky contact of diodes is formed by making a direct contact of an anode metal to the 2DEG channel the resulting structure minimizes an intrinsic junction capacitance due to the very thin contact area size. The low resistance of high-mobility 2DEG channel and a low contact resistance realized by a n+GaN ohmic regrowth layer reduce a series resistance of diodes as well as access resistance of the HEMT.

Abstract: A monolithically integrated device includes a substrate, a first set of Group III nitride epitaxial layers grown for a first HFET on a first region of the substrate, and a second set of Group III nitride epitaxial layers for a second HFET grown on a second region of the substrate.

Abstract: A system for forming self-aligned contacts includes electroplating a first metal contact onto a Group III-V semiconductor substrate, the first metal contact having a greater height than width and having a straight sidewall profile, etching back the semiconductor substrate down to a base layer to expose an emitter semiconductor layer under the first metal contact, conformally depositing a dielectric layer on a vertical side of the first metal contact, a vertical side of the emitter semiconductor layer and on the base layer, anisotropically etching the dielectric layer off of the semiconductor substrate to form a dielectric sidewall spacer on the vertical side of the first metal contact and providing a second metal contact immediately adjacent the dielectric sidewall spacer.

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: 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 gate structure for a field effect transistor having a buffer layer on a substrate, a channel layer and a barrier layer over the channel layer includes forming a gate of a first dielectric, forming first sidewalls of a second dielectric on either side and adjacent to the gate, selectively etching into the buffer layer to form a mesa for the field effect transistor, depositing a dielectric layer over the mesa, planarizing the dielectric layer over the mesa to form a planarized surface such that a top of the gate, tops of the first sidewalls, and a top of the dielectric layer over the mesa are on the same planarized surface, depositing metal on the planzarized surface, annealing to form the gate into a metal silicided gate, and etching to remove excess non-silicided metal.

Abstract: The interface resistance between the source/drain and gate of an HFET may be significantly reduced by engineering the bandgap of the 2DEG outside a gate region such that the charge density is substantially increased. The resistance may be further reduced by using an n+GaN Cap layer over the channel layer and barrier layer such that a horizontal surface of the barrier layer beyond the gate region is covered by the n+GaN Cap layer. This technique is applicable to depletion and enhancement mode HFETs.

Abstract: A system for forming self-aligned contacts includes electroplating a first metal contact onto a Group III-V semiconductor substrate, the first metal contact having a greater height than width and having a straight sidewall profile, etching back the semiconductor substrate down to a base layer to expose an emitter semiconductor layer under the first metal contact, conformally depositing a dielectric layer on a vertical side of the first metal contact, a vertical side of the emitter semiconductor layer and on the base layer, anisotropically etching the dielectric layer off of the semiconductor substrate to form a dielectric sidewall spacer on the vertical side of the first metal contact and providing a second metal contact immediately adjacent the dielectric sidewall spacer.

Abstract: A high electron mobility field effect transistor (HEMT) having a substrate, a channel layer on the substrate and a barrier layer on the channel layer includes a stress inducing layer on the barrier layer, the stress inducing layer varying the piezo-electric effect in the barrier layer in a drift region between a gate and a drain. A two dimensional electron gas (2DEG) has a non-uniform lateral distribution in the drift region between the gate and the drain.