Silicon Diffused Junction “Avalanche” Diodes

Silicon N+, P, P+ diffused junction diodes have been made by diffusion of B and P into p ‐type Si. Units have been fabricated with breakdown voltages from 6 to greater than 200 v, with areas from 5 × 10 − 3 cm 2 to 5 cm 2 . Design problems associated with high and low voltage diodes are discussed. Reverse saturation currents at half the breakdown voltage are often in the order of 10 −6 amp/cm 2 . Impedance after breakdown is shown to be a function of the breakdown voltage and the magnitude of the avalanche current. The cut‐off frequency is in the order of one megacycle, and is shown to increase with decreasing transition region capacitance. Some units with areas of 5 × 10 2 cm 2 have been operated at power levels of 10 w, with special provision for heat dissipation.