Silicon fusion transistors fabricated by aluminum evaporation

A PNP fused junction transistor has been developed using a process in which alloying of the silicon is obtained by evaporation of the aluminum alloying material onto the silicon blank. Using this method, collector junctions have been made as large as 1/8" square and emitter junctions as small as .010" in diameter. As the aluminum evaporated may be quite well controlled as to quantity and location on the silicon blank, transistors may be produced with reasonably uniform physical dimensions.