Abstract: Refractory metals or ceramics are diffusion bonded or densified by assembling the workpieces to be bonded, wrapping the assembly with carbon yarn, heating the wrapped assembly, cooling the assembly and unwrapping. The expansion of the workpieces together with the shrinking of the carbon yarn produces tremendous pressures which cause bonding and densifying of the workpiece.

Abstract: Refractory metals or ceramics are diffusion bonded or densified by assembling the workpieces to be bonded, wrapping the assembly with carbon yarn, heating the wrapped assembly, cooling the assembly and unwrapping. The expansion of the workpieces together with the shrinking of the carbon yarn produces tremendous pressures which cause bonding and densifying of the workpiece.

Abstract: Refractory metals or ceramics are diffusion bonded or densified by assembling the workpieces to be bonded, wrapping the assembly with carbon yarn, heating the wrapped assembly, cooling the assembly and unwrapping. The expansion of the workpieces together with the shrinking of the carbon yarn produces tremendous pressures which cause bonding and densifying of the workpiece.

Abstract: A linear beam tube has multiple heat pipes formed integrally in the cavity wall between the beam collector and external air cooling fins. The heat pipes use sintered copper pellets on the walls of the pipes as wicks to facilitate the return flow of liquid condensed at the fins. Circumferential channels connect the heat pipes at each end to reduce vapor lock effects. Vapor surface area enhancement rods are used at the heat source to increase the transfer rates of heat into the fluid.

Abstract: A transcalent semiconductor device comprises a body of semiconductor material having first and second major opposed surfaces. The first surface includes at least one region of first type conductivity and a region of opposite type conductivity. A first heat pipe having a conductive contact disc is in electrical and thermal contact with substantially all of the first surface. The conductive contact disc has an aperture therein. A control electrode for initiating conduction through the semiconductor material extends through the aperture in the disc and contacts the region of opposite type conductivity. A second heat pipe is disposed in electrical and thermal conductive relationship with the second surface. In an alternative embodiment, a fiber optic light pipe controls the initiation of conduction through the semiconductor material by transmitting photons to the region of opposite type conductivity.

Abstract: A semiconductor device comprises a body of semiconductor material having a base-emitter structure on a first surface of the body. The base emitter structure includes a plurality of discrete emitter regions interdigitated with a base region having a base contact on the base region. A base contact ring is attached coaxially to the base contact. An improved base terminal structure comprises a conductive base feed-through ring having a base terminal integral with the feed-through ring. The base feed-through ring is spaced from and concentric with the base contact ring. The base terminal structure further includes a resilient contact ring attached to the base contact ring and the base feed-through ring to provide a low impedance interconnection between the base contact ring and the base feed-through ring.

Abstract: A semiconductor power device comprises a semiconductor pellet having first and second opposing major surfaces, including, in series, emitter, base and collector regions of alternate conductivity type. The collector region is substantially planar and adjacent to the second surface, the base region is adjacent to the collector region and extends to the first surface, and the emitter region extends relatively deeply into the pellet from the first surface and is substantially surrounded by the base region. The emitter region substantially surrounds a substantially centrally located extension of the base region, this extension being of relatively high resistance and also terminating at the first surface. An emitter electrode contacts the emitter region and the base region extension, a collector electrode contacts the collector region, and a base electrode contacts the base region.

Abstract: The device includes a semiconductor wafer that is cooled on one side, and preferably on both sides, by a liquid cooling system. The system preferably comprises a cylindrical cooling chamber including a relatively thin thermally conductive base wall bonded directly to the wafer for good thermal contact. Liquid coolant is supplied to the base wall, which in turn cools the wafer, through a conduit terminating in a circular flange disposed within the chamber in close proximity to the base wall. The coolant is forced between the flange and base wall and is directed substantially over the entire base wall surface by the flange. The surface of the flange facing the base wall is formed to have a frustro-conical surface to reduce the pressure of the coolant as it flows constrictedly between the flange and base wall as well as to enhance the uniformity of heat transfer across the base wall and thus from the wafer.

Abstract: A semiconductor power device comprises a semiconductor pellet having first and second opposing major surfaces, including, in series, emitter, base and collector regions forming a PNP transistor. The collector region is substantially planar and adjacent to the second surface; the base region is adjacent to the collector region and extends to the first surface; and the emitter region extends into the pellet from the first surface such that it is substantially surrounded by the base region. The emitter region substantially surrounds a substantially centrally located extension of the base region which also terminates at the first surface. Emitter, base and collector electrodes are ohmically disposed on the respective semiconductor regions and a Schottky barrier contact is formed on the base region extension, the Schottky contact being connected to the emitter electrode.

Abstract: An improvement for a transcalent semiconductor device includes a semiconductor ballast resistor in contact with the emitter regions of a semiconductor transistor. The semiconductor transistor with the ballast resistor in contact therewith is sandwiched between two closed heat pipes wherein one heat pipe is in thermal and electrical contact with the transistor and the other heat pipe is in thermal and electrical contact with the resistor.