Silicon planar transistors and diodes for deep-water submarine cable repeaters

A detailed description is given of the methods used by S.T.C. Semiconductors to obtain reliable transistors and diodes for deep-water submarine repeater applications, and of the methods used to give assurance on reliability achievement. Silicon planar techniques were used for production: basic techniques were not modified but meticulous care was employed in production, inspection, and screening. For reliability assurance, basic design suitability, was checked by overstress tests: mechanical and electrical reliability, and the hermeticity of the devices, were checked by a severe mechanical thermal test, a 3-months operational burn-in, and by radioactive-krypton hermeticity testing. The mechanical test and the burn-in, and the number of devices tested, gave statistical assurance on reliability. The transistors and diodes passed all tests and are currently being built into deep-water submarine repeaters.