Abstract: Laterally-gated transistors and lateral Schottky diodes are disclosed. The FET includes a substrate, source and drain electrodes, channel, a gate electrode structure, and a dielectric layer. The gate electrode structure includes an electrode in contact with the channel and a lateral field plate adjacent to the electrode. The dielectric layer is disposed between the lateral field plate and the channel. The lateral field plate contacts the dielectric layer and to modulate an electric field proximal to the gate electrode proximal to the drain or source electrodes. Also disclosed is a gate electrode structure with lateral field plates symmetrically disposed relative to the gate electrode. Also disclosed in a substrate with dielectric structures buried in the substrate remote from the gate electrode structure. A lateral Schottky diode having an anode structure includes an anode (A), cathodes (C) and lateral field plates located between the anode and the cathodes.

Abstract: A method of forming a bipolar transistor with a vertical collector contact requires providing a transistor comprising a plurality of epitaxial semiconductor layers on a first substrate, and providing a host substrate. A metal collector contact is patterned on the top surface of the host substrate, and the plurality of epitaxial semiconductor layers is transferred from the first substrate onto the metal collector contact on the host substrate. The first substrate is suitably the growth substrate for the plurality of epitaxial semiconductor layers. The host substrate preferably has a higher thermal conductivity than does the first substrate, which improves the heat dissipation characteristics of the transistor and allows it to operate at higher power densities. A plurality of transistors may be transferred onto a common host substrate to form a multi-finger transistor.

Abstract: Laterally-gated transistors and lateral Schottky diodes are disclosed. The FET includes a substrate, source and drain electrodes, channel, a gate electrode structure, and a dielectric layer. The gate electrode structure includes an electrode in contact with the channel and a lateral field plate adjacent to the electrode. The dielectric layer is disposed between the lateral field plate and the channel. The lateral field plate contacts the dielectric layer and to modulate an electric field proximal to the gate electrode proximal to the drain or source electrodes. Also disclosed is a gate electrode structure with lateral field plates symmetrically disposed relative to the gate electrode. Also disclosed in a substrate with dielectric structures buried in the substrate remote from the gate electrode structure. A lateral Schottky diode having an anode structure includes an anode (A), cathodes (C) and lateral field plates located between the anode and the cathodes.

Abstract: A method of forming a bipolar transistor with a vertical collector contact requires providing a transistor comprising a plurality of epitaxial semiconductor layers on a first substrate, and providing a host substrate. A metal collector contact is patterned on the top surface of the host substrate, and the plurality of epitaxial semiconductor layers is transferred from the first substrate onto the metal collector contact on the host substrate. The first substrate is suitably the growth substrate for the plurality of epitaxial semiconductor layers. The host substrate preferably has a higher thermal conductivity than does the first substrate, which improves the heat dissipation characteristics of the transistor and allows it to operate at higher power densities. A plurality of transistors may be transferred onto a common host substrate to form a multi-finger transistor.

Abstract: A FET with a buried gate structure. The FET's gate electrode comprises a plurality of buried gate structures, the tops of which extend above the substrate's top surface and the bottoms of which are buried to a depth at least equal to that of the bottom of the channel layer, or the 2DEG plane within a channel layer for a HEMT, such that the buried gate structures contact the channel layer only from its sides. A head portion above and not in contact with the substrate's top surface contacts the tops of and interconnects all of the buried gate structures. Drain current is controlled by channel width modulation by lateral gating of the channel layer by the buried gates structures. The FET may include at least one field plate which comprises a slit structure in which the field plate is divided into segments.

Abstract: A FET employing a micro-scale device array structure comprises a substrate on which an epitaxial active channel area has been grown, with a plurality of micro-cells uniformly distributed over the active channel area. Each micro-cell comprises a source electrode, a drain electrode, and at least one gate electrode, with a first metal layer interconnecting either the drain or the source electrodes, a second metal layer interconnecting the gate electrodes, and a third metal layer interconnecting the other of the drain or source electrodes. Each micro-cell preferably comprises a source or drain electrode at the center of the micro-cell, with the corresponding drain or source electrode surrounding the center electrode. The number and width of the gate electrodes in each micro-cell may be selected to achieve a desired power density and/or heat distribution, and/or to minimize the FET's junction temperature. The FET structure may be used to form, for example, HEMTs or MESFETs.

Abstract: A FET with a buried gate structure. The FET's gate electrode comprises a plurality of buried gate structures, the tops of which extend above the substrate's top surface and the bottoms of which are buried to a depth at least equal to that of the bottom of the channel layer, or the 2DEG plane within a channel layer for a HEMT, such that the buried gate structures contact the channel layer only from its sides. A head portion above and not in contact with the substrate's top surface contacts the tops of and interconnects all of the buried gate structures. Drain current is controlled by channel width modulation by lateral gating of the channel layer by the buried gates structures. The FET may include at least one field plate which comprises a slit structure in which the field plate is divided into segments.

Abstract: A FET employing a micro-scale device array structure comprises a substrate on which an epitaxial active channel area has been grown, with a plurality of micro-cells uniformly distributed over the active channel area. Each micro-cell comprises a source electrode, a drain electrode, and at least one gate electrode, with a first metal layer interconnecting either the drain or the source electrodes, a second metal layer interconnecting the gate electrodes, and a third metal layer interconnecting the other of the drain or source electrodes. Each micro-cell preferably comprises a source or drain electrode at the center of the micro-cell, with the corresponding drain or source electrode surrounding the center electrode. The number and width of the gate electrodes in each micro-cell may be selected to achieve a desired power density and/or heat distribution, and/or to minimize the FET's junction temperature. The FET structure may be used to form, for example, HEMTs or MESFETs.

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 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 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 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 mask layer is applied to a surface of a semiconductor structure or a seed layer deposited on the surface. The mask layer has a submicron width opening with a high aspect ratio that exposes a portion of the surface or seed layer. Conductive material is conformed to the opening, for example by plating, to form a first contact on the surface or seed layer. The mask and the top layer of the semiconductor structure, except for the portion under the first contact, are removed to expose a second layer of the semiconductor structure. An insulating layer is formed along the sidewalls of the first contact and the top layer of the semiconductor structure beneath the first contact. A mask is then applied to the second layer and a second contact is formed by selectively depositing metal only on the portion of the second layer exposed by the opening.