Prediction of avalanche breakdown voltage in silicon step junctions

Abstract

The results of two major theories that attempt to predict the electric field dependence of the ionization rates in silicon are compared with experimental data. For this purpose the published ionization rule measurements BUS supplemented by using the results of the two theories to predict the breakdown voltages of silicon step junctions. It is found that a. discrepancy between Baraff's analysis and the ionization rate data is also present in the comparison with breakdown voltage measurements. In contrast, a satisfactory agreement with both sets of results is found using the simple ballistic model first introduced by Shockley. The analysis of Shockley's model is re-examined with particular reference to certain discrepancies found by earlier workers. A revised expression for the ionization rate is obtained which removes the discrepancies and also remains consistent with both Shockley's earlier analysis and the experimental data.