GB1408063A - Silicon-based semiconductor devices - Google Patents

Abstract

1408063 Transistors SIEMENS AG 6 July 1973 [17 July 1972] 32355/73 Addition to 1310449 Heading H1K In manufacture, in order to improve the radiation resistance and stability of a transistor comprising a body of silicon oxide coated silicon, the body is irradiated with electrons of energy less than 150 keV for a sufficient time to give a dosage at the oxide silicon interface of 10<SP>9</SP> to 10<SP>10</SP> rads while maintained between 200‹ and 300‹ C. The body is then subjected to heat treatment at 200-300‹ C. for at least ten hours without further irradiation but with a forward bias of at least 0À3 volt maintained between its emitter and base connections. Typically an NPN planar transistor without, or with an unsealed housing is irradiated in an evacuated chamber on a heated copper plate. The housing may be evacuated or filled with dry protective gas and sealed either before or immediately after the following heat treatment, during which the collector junction is preferably also forward biased. Alternatively protection of the device is afforded by covering the body with silicone or polyimide resin before sealing the casing, or by merely coating the body with moisture repellent silicone resin. Where several transistor configurations are formed in the same body division into single components and electroding may be effected after irradiation, but if the body is to constitute an integrated circuit electroding is done before irradiation.