One-dimensional calculation of thyristor forward voltages and holding currents

Abstract

One-dimensional numerical analysis of complete semiconductor device equations is applied to the p-n-p-n four layer structure with an arbitrary impurity doping profile and arbitrary carrier lifetimes, to calculate the thyristor DC forward voltages and the holding current. In the beginning, a numerical method of the current-control type is presented, with discussion about the convergence of the iterative process involved. Then a set of standard numerical values is given to the parameters to describe the impurity doping condition. Computation results are demonstrated for a variety of carrier lifetimes and current densities. Endeavor will be made to understand basic device physics through the computed carrier densities, electric fields, potentials and currents. The computation results also include the static current vs voltage characteristics, which are immediately concerned with the actual design and fabrication of thyristors. Specifically for the design of high speed thyristors, a preferable condition is provided by keeping lifetimes in the shorter base to a high value and those in the longer base to a low value.