Investigation into the effect of Auger recombination on charge carrier transport and static characteristics of silicon multilayer structures

Abstract

A new model for charge carrier transport through a silicon multilayer structure at high current density is presented. This model accounts for a number of nonlinear physical phenomena (electron-hole scattering, Auger recombination, high doping effects) which become of significance at high current density. The injected charge carrier distribution in the lightly doped layer of the structure at high current density was investigated on the basis of this model and previously predicted phenomenon of injected carrier saturation is confirmed. The dependence of injected carrier limiting density on the electrophysical parameters of the silicon structure was investigated. Within the framework of the suggested model the current-voltage characteristics of a p +- n- n + structure was studied. It is demonstrated that injected carrier saturation phenomenon results in linear current-voltage characteristics at high current densities. A characteristic ratio ( W L ) c (where W is the width of the n-base layer and L is the ambipolar diffusion length of charge carriers in the n-base layer) was found to divide the diode structures into two groups. In the first group with W L <( W L ) c the recombination of injected carriers in the n-base layer at high current density is provided by Auger processes only and therefore the current-voltage characteristics does not depend on lifetime τ, conditioned by the Shockley-Read-Hall recombination processes. The second group of structures with W L >( W L ) c retains a dependence on τ at all current densities. Experimental data presented in the last section of the article confirm the results of device modeling.