Improvements in or relating to semiconductor devices

摘要

In a semi-conductor diode, Fig. 1, a silicon wafer 11, coated with a gold layer 15, is sealed to a ceramic ring 17, the undersurface of which is gold-plated, by the interposition of a gold electrode 16 and a gold disc 19. Sealing is effected by fusion in an inert atmosphere, e.g. a rare gas, N2, CO2, CO, or in an active atmosphere such as O2 or water vapour, or in a vacuum. In Fig. 6, a silicon wafer 54 is sealed to a cover 51 of glass or ceramic, through which two metal conductors 52 are sealed, by a glass or metal ring 57. In Fig. 8, a silicon wafer 85 mounted on a molybdenum plate 86 is sealed to two blocks 83 of ceramic or glass, each block having a foil electrode 81, 82 of Mo-As and Mo respectively bonded thereto, by glass seals 84, 87 between the electrodes and around the periphery of the wafer respectively. In addition to Mo, tantalum, tungsten and "Kovar" (Registered Trade Mark), are compatible in expansion properties with silicon and with glass such as "Corning" (Registered Trade Mark) 7052, the approximate composition of which is said to be B2O3, 15% by weight; SiO2, 65%; Al2O3, 8%; Na2O, 2%; BaO, 2%; Li2O, 8%. A suitable ceramic for use with the above is: California talc (approximately 3MgO.4 SiO2.H2O), 80 parts by weight; Florida plastic kaolin (approximately Al2O3.2 SiO2.2H2O), 20 parts; MgCO3, 10 parts; BaCO3, 23.4 parts. A further set of matching metal, glass and ceramic is Dumet alloy (46% Ni, 54% Fe, plated or sheathed with Cu), "Corning" (Registered Trade Mark) glasses 0080, and ceramics Alsimag 35 and 196.