Open-base Breakdown in Diffused N-P-N Junction Transistors†

Abstract

ABSTRACT A one-dimensional analysis is presented on the open-base breakdown characteristics of diffused n-p-n transistors. From breakdown voltage measurements upon selected devices—in conjunction with breakdown voltage calculations—‘ effective ’ values are established for the ionization rate of electrons in germanium and silicon p-n junctions, when biased substantially below avalanche breakdown. These ‘ effective ’ electron ionization rates are used to calculate the open-base breakdown voltage for transistors exhibiting a large collector punch-through voltage ; such calculations are graphically illustrated throughout iv range of parameters applicable to many practical situations. A discussion is also presented on the influence of an abrupt conductivity increase within the collector junction space-charge layer, of the typo encountered in an idealized epitaxial structure.