Network Analysis Approach to Multidimensional Modeling of Transistors Including Thermal Effects

A comprehensive numerical model for simulating the electrical and thermal behavior of a bipolar transistor is developed. The proposed model is in the form of an electrical network for its easy implementation using a circuit analysis program. One of the suggested solution techniques enables us to simulate a fairly large problem with a reasonable amount of computer time. The effect of temperature dependence of thermal conductivity of the device material upon thermal instability is shown. It is described how the model can be used to find the appropriate values of ballasting resistors desired for the improvement of thermal stability. Prediction of a safe operating area using the proposed model is also reported.