Abstract: A composite-layer semiconductor device includes a gate above a host substrate, an n++ contact layer above the gate, and source and drain ohmic contacts applied to the n++ contact layer. The source and drain ohmic contacts define a central gate location which is recessed through the n++ contact layer toward the gate. The source and drain ohmic contacts create a barrier to chemical etching so that a current path below the central gate location can be incrementally recessed in repeated steps to precisely tailor the operating mode of the device for depletion or enhancement applications. The composite-layer semiconductor device is fabricated by depositing a gate on an n++ contact layer above a semi-insulating substrate. The semi-insulating substrate and gate are flipped onto an epoxy layer on the host substrate so that the gate is secured to the epoxy layer and the semi-insulating substrate presents an exposed backside. A portion of the exposed backside is removed.

Abstract: A composite-layer semiconductor device includes a gate above a host substrate, an n++ contact layer above the gate, and source and drain ohmic contacts applied to the n++ contact layer. The source and drain ohmic contacts define a central gate location which is recessed through the n++ contact layer toward the gate. The source and drain ohmic contacts create a barrier to chemical etching so that a current path below the central gate location can be incrementally recessed in repeated steps to precisely tailor the operating mode of the device for depletion or enhancement applications. The composite-layer semiconductor device is fabricated by depositing a gate on an n++ contact layer above a semi-insulating substrate. The semi-insulating substrate and gate are flipped onto an epoxy layer on the host substrate so that the gate is secured to the epoxy layer and the semi-insulating substrate presents an exposed backside. A portion of the exposed backside is removed.

Abstract: A photo FET device having a large area backside optical energy reception surface is disclosed. The photo FET device is fabricated in the source gate and drain upward configuration and then inverted onto a new permanent substrate member and an original surrogate substrate member removed in order to expose the active area backside optical energy reception surface. Electrical characteristics including curve tracer electrical data originating in both dark and illuminated devices and devices of varying size and both depletion mode and enhancement mode operation are also disclosed. Fabrication of the device from gallium arsenide semiconductor material and utilization for infrared energy transducing in a number of differing electronic applications are also disclosed.

Abstract: A photo FET device having a large area backside optical energy reception surface is disclosed. The photo FET device is fabricated in the source gate and drain upward configuration and then inverted onto a new permanent substrate member and an original surrogate substrate member removed in order to expose the active area backside optical energy reception surface. Electrical characteristics including curve tracer electrical data originating in both dark and illuminated devices and devices of varying size and both depletion mode and enhancement mode operation are also disclosed. Fabrication of the device from gallium arsenide semiconductor material and utilization for infrared energy transducing in a number of differing electronic applications are also disclosed.

Abstract: A high temperature resist process is combined with microlithographic patterning for the production of materials, such as diamond films, that require a high temperature deposition environment. A conventional polymeric resist process may be used to deposit a pattern of high temperature resist material. With the high temperature resist in place and the polymeric resist removed, a high temperature deposition process may proceed without degradation of the resist pattern. After a desired film of material has been deposited, the high temperature resist is removed to leave the film in the pattern defined by the resist. For diamond films, a high temperature silicon nitride resist can be used for microlithographic patterning of a silicon substrate to provide a uniform distribution of diamond nucleation sites and to improve diamond film adhesion to the substrate.

Abstract: The method of constructing an air bridge on a substrate between spaced apart conductors on the substrate with the bridge spanning the distance between the conductors, by using PMGI to build a bridge pad on the substrate; using PMMA to build a bridge pattern over the pad with the ends of said conductors extending into said pattern; depositing titanium and gold over said pad within said pattern by directing the titanium and gold into said pattern onto said pad and conductor ends using relative motion between the substrate and the titanium and gold; and removing the PMGI and PMMA.

Abstract: A mask and lithographic process is disclosed for the formation of conductive patterns on substrates, particularly in connection with the formation of high electron mobility transistors (HEMT) and metal-semiconductor field effect transistors (MESFET). The technique allows the formation of sub-half micron conductive patterns on semiconductor substrates using optical lithography and a multilayer portable conformable mask. The method includes the application of optical contact lithography to a conventional photoresist followed by a deep UV flood exposure of an underlying multilayer PMGI portion. Metal is deposited on a semiconductor substrate through the mask formed by the photoresist and PMGI layers to produce sub-half micron conductive patterns.