Diffused Emitter and Base Silicon Transistors*

Silicon n-p-n transistors have been made in which the base and emitter regions were produced by diffusing impurities from the vapor phase. Transistors with base layers 3.8 × 10 −4 -cm thick have been made. The diffusion techniques and the processes for making electrical contact to the structures are described. The electrical characteristics of a transistor with a maximum alpha of 0.97 and an alpha-cutoff of 120 mc/sec are presented. The manner in which some of the electrical parameters are determined by the distribution of the doping impurities is discussed. Design data for the diffused emitter, diffused base structure is calculated and compared with the measured characteristics.