Abstract: An Ohmic contact to a semiconductor body includes a thin semiconductor layer disposed between the body and a conductive layer. The thin layer is not alloyed to the conductive layer and not lattice matched to the body. The layer can have a thickness of less than about 100 nm and a lattice mismatch of at least 0.5 percent. Since the thin layer is not alloyed, a Schottky contact can be formed at the same time as the ohmic contact.

Abstract: The electron mobility in an active layer on a semi-insulating substrate is enhanced by initially performing a high energy implantation of an element which is inert in the semi-insulating material. Donor ions are then implanted so as to form the active layer in that area of the substrate in which the high energy implantation was performed, and the substrate is annealed.

Abstract: A method of pattern generating a circuit film and adjacent barrier film on a substrate. A continuous layer of circuit film is applied to the substrate surface, and a photoresist pattern is delineated on the circuit film such that the photoresist remains on the circuit film pattern area. The area of circuit film not covered by photoresist is then removed, exposing the substrate surface. While retaining the photoresist which covers the circuit film pattern, the entire substrate surface is coated with the barrier film. The remaining photoresist is then removed, causing the barrier film which covers it to lift off, thereby exposing the circuit film pattern.

Abstract: A fast-switching pulse modulator for generating a high-power output pulse in response to a low-power input pulse to apply a bias signal to a microwave apparatus having a high efficiency avalanche semiconductor diode such as a TRAPATT diode or IMPATT diode formed of GaAs. The modulator uses a transistor operating in a switching mode. The transistor is biased to a non-conducting state preferably by a negative D.C. bias voltage and switched to a first conducting mode upon application of the positive input pulse to the transistor. At this first conducting mode the transistor switches current from zero to a low-current level during which no RF output signal exists. Upon application of a threshold signal to, for example, the TRAPATT diode, the diode is triggered into the TRAPATT mode generating thereby an RF output pulse. As the diode is triggered into the TRAPATT mode the transistor is switched to a second conducting mode at a high current level.

Abstract: Solar radiation is concentrated on a solar cell of a photovoltaic device in the range of 500 to 1600 suns. the photovoltaic device includes a plurality of solar cells on a flat surface of a heat sink, and means for concentrating solar radiation on the solar cells. The solar cells have a surface on which the solar light is incident. This high concentration of solar energy on the solar cell will increase the solar cell operating temperature. The dimensions of the solar cells and the center to center spacing between solar cells is such that good thermal dissipation is maintained in the photovoltaic device.

Abstract: A planar TRAPATT diode includes a substrate selected from an area of a silicon wafer, a diffused region within the area, a mask of an insulating layer of SiO.sub.2, and a conductive layer of polycrystalline silicon. The silicon wafer includes a doped P region adjacent to the surface thereof and a heavily doped P.sup.+ region adjacent to the P region. The TRAPATT junction is a selected area below the surface at the interface between the diffused region, which is N.sup.+, and the P region. The polycrystalline silicon layer is the dopant source for the N.sup.+ diffused region and contacts the wafer in the selected area.

Abstract: Apparatus for mounting a diode in a microwave circuit for making electrical contact between the circuit and ground and for dissipation of heat between the diode and a heat sink. The diode, supported on a thermally and electrically conductive member, is resiliently pressed in electrical contact with the microwave circuit. A tapered collar on the member is elastically deformably wedged into a tapered aperture formed in a heat sink. The wedged collar tightens firmly around the member establishing good thermal and electrical conduction from the diode to the heat sink and ground. Disassembly is facilitated because of the elastically deformed collar.