A hybrid approach to heat transfer modeling in electrothermal models of power semiconductor devices

The numerical physical models of power semiconductor devices, based on a solution of the full set of semiconductor equations, are an efficient tool in the CAD technique. Until now a lot of such numerical modes, both 1-D and 2-D, have been reported, but only a few of them include thermal phenomena. The introduction of inner feedback between electrical and thermal phenomena into the models involves some technical problem arising from the fact that in such a model only a small part of the device, limited to the semiconductor chip, is considered, whereas the thermal properties of the device are determined, to a high degree, by its other parts. In the paper a new approach to heat transfer modeling in electrothermal physical models, called a hybrid approach, is presented. It consists of combining in one thermal submodel both a numerical simulation of heat transfer in the area of the semiconductor chip and a non-numerical simulation (based on the thermal resistance concept) in the other parts of the device. The presentation is illustrated by some examples of results obtained by means of an electrothermal model of a thyristor structure worked out by the author