Abstract: AlGaN/GaN HEMTs are disclosed having a thin AlGaN layer to reduce trapping and also having additional layers to reduce gate leakage and increase the maximum drive current. One HEMT according to the present invention comprises a high resistivity semiconductor layer with a barrier semiconductor layer on it. The barrier layer has a wider bandgap than the high resistivity layer and a 2DEG forms between the layers. Source and drain contacts contact the barrier layer, with part of the surface of the barrier layer uncovered by the contacts. An insulating layer is included on the uncovered surface of the barrier layer and a gate contact is included on the insulating layer. The insulating layer forms a barrier to gate leakage current and also helps to increase the HEMT's maximum current drive. The invention also includes methods for fabricating HEMTs according to the present invention. In one method, the HEMT and its insulating layer are fabricated using metal-organic chemical vapor deposition (MOCVD).

Abstract: A method of fabricating a III-N device includes forming a III-N channel layer on a substrate, a III-N barrier layer on the channel layer, an insulator layer on the barrier layer, and a trench in a first portion of the device. Forming the trench comprises removing the insulator layer and a part of the barrier layer in the first portion of the device, such that a remaining portion of the barrier layer in the first portion of the device has a thickness away from a top surface of the channel layer, the thickness being within a predetermined thickness range, annealing the III-N device in a gas ambient including oxygen at an elevated temperature to oxidize the remaining portion of the barrier layer in the first portion of the device, and removing the oxidized remaining portion of the barrier layer in the first portion of the device.

Abstract: Enhancement mode III-nitride devices are described. The 2DEG is depleted in the gate region so that the device is unable to conduct current when no bias is applied at the gate. Both gallium face and nitride face devices formed as enhancement mode devices.

Abstract: A method of fabricating a III-N device includes forming a III-N channel layer on a substrate, a III-N barrier layer on the channel layer, an insulator layer on the barrier layer, and a trench in a first portion of the device. Forming the trench comprises removing the insulator layer and a part of the barrier layer in the first portion of the device, such that a remaining portion of the barrier layer in the first portion of the device has a thickness away from a top surface of the channel layer, the thickness being within a predetermined thickness range, annealing the III-N device in a gas ambient including oxygen at an elevated temperature to oxidize the remaining portion of the barrier layer in the first portion of the device, and removing the oxidized remaining portion of the barrier layer in the first portion of the device.

Abstract: A III-N device is described has a buffer layer, a first III-N material layer on the buffer layer, a second III-N material layer on the first III-N material layer on an opposite side from the buffer layer and a dispersion blocking layer between the buffer layer and the channel layer. The first III-N material layer is a channel layer and a compositional difference between the first III-N material layer and the second III-N material layer induces a 2DEG channel in the first III-N material layer. A sheet or a distribution of negative charge at an interface of the channel layer and the dispersion blocking layer confines electrons away from the buffer layer.

Abstract: An electronic component includes a high-voltage depletion-mode transistor and a low-voltage enhancement-mode transistor both encased in a single package. A source electrode of the high-voltage depletion-mode transistor is electrically connected to a drain electrode of the low-voltage enhancement-mode transistor, a drain electrode of the high-voltage depletion-mode transistor is electrically connected to a drain lead of the single package, a gate electrode of the low-voltage enhancement-mode transistor is electrically connected to a gate lead of the single package, a gate electrode of the high-voltage depletion-mode transistor is electrically connected to an additional lead of the single package, and a source electrode of the low-voltage enhancement-mode transistor is electrically connected to a conductive structural portion of the single package.

Abstract: A III-N semiconductor device that includes a substrate and a nitride channel layer including a region partly beneath a gate region, and two channel access regions on opposite sides of the part beneath the gate. The channel access regions may be in a different layer from the region beneath the gate. The device includes an AlXN layer adjacent the channel layer wherein X is gallium, indium or their combination, and a preferably n-doped GaN layer adjacent the AlXN layer in the areas adjacent to the channel access regions. The concentration of Al in the AlXN layer, the AlXN layer thickness and the n-doping concentration in the n-doped GaN layer are selected to induce a 2DEG charge in channel access regions without inducing any substantial 2DEG charge beneath the gate, so that the channel is not conductive in the absence of a switching voltage applied to the gate.

Abstract: Transistor devices which include semiconductor layers with integrated hole collector regions are described. The hole collector regions are configured to collect holes generated in the transistor device during operation and transport them away from the active regions of the device. The hole collector regions can be electrically connected or coupled to the source, the drain, or a field plate of the device. The hole collector regions can be doped, for example p-type or nominally p-type, and can be capable of conducting holes but not electrons.

Abstract: A III-N semiconductor HEMT device includes an electrode-defining layer on a III-N material structure. The electrode-defining layer has a recess with a first sidewall proximal to the drain and a second sidewall proximal to the source, each sidewall comprising a plurality of steps. A portion of the recess distal from the III-N material structure has a larger width than a portion of the recess proximal to the III-N material structure. An electrode is in the recess, the electrode including an extending portion over the first sidewall. A portion of the electrode-defining layer is between the extending portion and the III-N material structure. The first sidewall forms a first effective angle relative to the surface of the III-N material structure and the second sidewall forms a second effective angle relative to the surface of the III-N material structure, the second effective angle being larger than the first effective angle.

Abstract: An electronic component includes a high-voltage depletion-mode transistor and a low-voltage enhancement-mode transistor. A source electrode of the high-voltage depletion-mode transistor is electrically connected to a drain electrode of the low-voltage enhancement-mode transistor, and a gate electrode of the high-voltage depletion-mode transistor is electrically coupled to the source electrode of the low-voltage enhancement-mode transistor. The on-resistance of the enhancement-mode transistor is less than the on-resistance of the depletion-mode transistor, and the maximum current level of the enhancement-mode transistor is smaller than the maximum current level of the depletion-mode transistor.

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: A method of fabricating a III-N device includes forming a III-N channel layer on a substrate, a III-N barrier layer on the channel layer, an insulator layer on the barrier layer, and a trench in a first portion of the device. Forming the trench comprises removing the insulator layer and a part of the barrier layer in the first portion of the device, such that a remaining portion of the barrier layer in the first portion of the device has a thickness away from a top surface of the channel layer, the thickness being within a predetermined thickness range, annealing the III-N device in a gas ambient including oxygen at an elevated temperature to oxidize the remaining portion of the barrier layer in the first portion of the device, and removing the oxidized remaining portion of the barrier layer in the first portion of the device.

Abstract: A circuit substrate has one or more active components and a plurality of passive circuit elements on a first surface. An active semiconductor device has a substrate with layers of material and a plurality of terminals. The active semiconductor device is flip-chip mounted on the circuit substrate and at least one of the terminals of the device is electrically connected to an active component on the circuit substrate. The active components on the substrate and the flip-chip mounted active semiconductor device, in combination with passive circuit elements, form preamplifiers and an output amplifier respectively. In a power switching configuration, the circuit substrate has logic control circuits on a first surface. A semiconductor transistor flip-chip mounted on the circuit substrate is electrically connected to the control circuits on the first surface to thereby control the on and off switching of the flip-chip mounted device.

Abstract: Semiconductor device structures and methods of fabricating semiconductor devices structures are provided that include a semi-insulating or insulating GaN epitaxial layer on a conductive semiconductor substrate and/or a conductive layer. The semi-insulating or insulating GaN epitaxial layer has a thickness of at least about 4 ?m. GaN semiconductor device structures and methods of fabricating GaN semiconductor device structures are also provided that include an electrically conductive SiC substrate and an insulating or semi-insulating GaN epitaxial layer on the conductive SiC substrate. The GaN epitaxial layer has a thickness of at least about 4 ?m.

Abstract: Semiconductor devices with guard rings are described. The semiconductor devices may be, e.g., transistors and diodes designed for high-voltage applications. A guard ring is a floating electrode formed of electrically conducting material above a semiconductor material layer. A portion of an insulating layer is between at least a portion of the guard ring and the semiconductor material layer. A guard ring may be located, for example, on a transistor between a gate and a drain electrode. A semiconductor device may have one or more guard rings.

Abstract: A III-N device is described with a III-N layer, an electrode thereon, a passivation layer adjacent the III-N layer and electrode, a thick insulating layer adjacent the passivation layer and electrode, a high thermal conductivity carrier capable of transferring substantial heat away from the III-N device, and a bonding layer between the thick insulating layer and the carrier. The bonding layer attaches the thick insulating layer to the carrier. The thick insulating layer can have a precisely controlled thickness and be thermally conductive.

Abstract: A III-N semiconductor device that includes a substrate and a nitride channel layer including a region partly beneath a gate region, and two channel access regions on opposite sides of the part beneath the gate. The channel access regions may be in a different layer from the region beneath the gate. The device includes an AlXN layer adjacent the channel layer wherein X is gallium, indium or their combination, and a preferably n-doped GaN layer adjacent the AlXN layer in the areas adjacent to the channel access regions. The concentration of Al in the AlXN layer, the AlXN layer thickness and the n-doping concentration in the n-doped GaN layer are selected to induce a 2DEG charge in channel access regions without inducing any substantial 2DEG charge beneath the gate, so that the channel is not conductive in the absence of a switching voltage applied to the gate.

Abstract: A transistor device is described that includes a source, a gate, a drain, a semiconductor material which includes a gate region between the source and the drain, a plurality of channel access regions in the semiconductor material on either side of the gate, a channel in the semiconductor material having an effective width in the gate region and in the channel access regions, and an isolation region in the gate region. The isolation region serves to reduce the effective width of the channel in the gate region without substantially reducing the effective width of the channel in the access regions. Alternatively, the isolation region can be configured to collect holes that are generated in the transistor device. The isolation region may simultaneously achieve both of these functions.

Abstract: Transistor devices which include semiconductor layers with integrated hole collector regions are described. The hole collector regions are configured to collect holes generated in the transistor device during operation and transport them away from the active regions of the device. The hole collector regions can be electrically connected or coupled to the source, the drain, or a field plate of the device. The hole collector regions can be doped, for example p-type or nominally p-type, and can be capable of conducting holes but not electrons.

Abstract: An electronic component includes a high-voltage depletion-mode transistor and a low-voltage enhancement-mode transistor. A source electrode of the high-voltage depletion-mode transistor is electrically connected to a drain electrode of the low-voltage enhancement-mode transistor, and a gate electrode of the high-voltage depletion-mode transistor is electrically coupled to the source electrode of the low-voltage enhancement-mode transistor. The on-resistance of the enhancement-mode transistor is less than the on-resistance of the depletion-mode transistor, and the maximum current level of the enhancement-mode transistor is smaller than the maximum current level of the depletion-mode transistor.