Improvements in or relating to the Manufacture of Germanium Planar Transistors

摘要

1,178,058. Semi-conductor devices. SIEMENS A.G. 20 Oct., 1967 [21 Oct., 1966], No. 47803/67. Heading H1K. In a method of manufacturing a germanium PNP planar transistor by diffusing doping agents through windows in the surface masking layer 7 of the crystal 1, the diffusion of the doping agent for the emitter 6 is carried out under conditions such that the portion of the collector-base junction opposite the emitter region 6 is substantially prevented from further penetration into the crystal whilst the remainder of the collector-base junction 3 penetrates a further appreciable distance into the crystal to produce a base region 4 which is H-shaped in cross-section taken in a median plane perpendicular to the crystal surface. The lateral distance d between the edge of the window 9 through which the emitter impurity is to be diffused and the collector junction and the penetration depth D of the base zone prior to diffusion of the emitter doping agent must satisfy the condition d # 2D. The doping agents used are indium for the collector 2, phosphorus at a concentration of 1019 atoms/cc. or arsenic at a concentration of 1019-1020 atoms/cc. for the base 4 and aluminium or boron at a concentration of 1021 atoms/c.c. for the emitter 6. The masking layers 7a, 7b are of chemically deposited silicon oxide or silicon nitride.