Abstract: The junctions of a plurality of semiconductor devices are formed in a common wafer. The upper surface of the common wafer is metallized for each of the individual devices by a nickel, chromium, nickel, silver metallizing system. Individual wafer elements are thereafter separated from the main wafer and their bottom surfaces are vacuum-alloyed to a molybdenum expansion plate. Thereafter, the outer periphery of the devices is tapered by grinding and the periphery is etched by hot potassium hydroxide without need to protect the upper metallizing from the etch. The caustic etch is washed with citric acid. Thereafter, the periphery is passivated by a passivation coating.

Abstract: The junctions of a plurality of semiconductor devices are formed in a common wafer. The upper surface of the common wafer is metallized for each of the individual devices by a nickel, chromium, nickel, silver metallizing system. Individual wafer elements are thereafter separated from the main wafer and their bottom surfaces are vacuum-alloyed to a molybdenum expansion plate. Thereafter, the outer periphery of the devices is tapered by grinding and the periphery is etched by hot potassium hydroxide without need to protect the upper metallizing from the etch. The caustic etch is washed with citric acid. Thereafter, the periphery is passivated by a passivation coating.

Abstract: A controlled rectifier employing a ring gate and an auxiliary emitter is disclosed. Auxiliary gates of different sensitivity cooperate with the auxiliary emitter. The controlled rectifier has gallium-diffused junctions and a phosphorus-diffused emitter. Phosphorus gettering dots or rings are diffused into the gallium-diffused region at the upper surface of the device surrounding and beneath portions of the ring gate electrode. The ring gate electrode has a narrow finger which extends from its internal periphery and overlaps a narrow extension from the main central emitter in order to provide a non-injecting current path for the peripheral distributed capacitance current which flows during the application of forward voltage. The value of this current is proportional to the rate of application of voltage or dV/dt.

Abstract: Coplanar interdigitated gate and emitter contacts are accessible at the surface of a large area wafer forming a high power, high speed controlled rectifier. A pressure contact is made to the emitter contact which is raised above the level of the gate contact. The upper surface of the gate contact is anodized to provide an insulation layer which prevents accidental shorting of the gate to the emitter contact.

Abstract: A semiconductor device comprises a semiconductor wafer arranged between metallic connecting members for supplying electric current to, and leading it from, the wafer, each connecting member having a substantially cylindrical external part. A ring of a sulphone polymer or of polyphenylene sulphide, which may be reinforced with glass fibre material, has portions of its internal peripheral surface surrounding and firmly engaged with the cylindrical parts of the connecting members, the ring and the connecting members forming a protective casing around the semiconductor wafer.