A high power, high voltage diffused germanium transistor

A high power, high voltage germanium transistor has been fabricated using solid-state diffusion to form the emitter and collector junctions. The collector junction is designed to give high breakdown voltage. This is obtained through a low surface concentration and shallow gradient. The emitter junction approximates a step junction to give high emitter efficiency. The NPN transistor is made using a 15-25 Ω cm P-type pellet. The collector diffusion is a carefully controlled two-step process. A skin of antimony is formed from a powdered antimony germanium source. The collector junction is formed by a subsequent diffusion. The emitter diffusion utilizes an arsenic germanium source to obtain high surface concentration.