The current mirror thermal characterization method and its implementation in a power SOI BJT process

Abstract

A new current mirror method is described that can be used to evaluate thermal issues in silicon-on-insulator (SO0 bipolar junction transistors (BJTs). This method is compared to conventional transistor level techniques ond is shown to significantly improve safe operating area (SOA) measurement sensitiviq. Unlike conventional metho&, the current mirror method can provide quantitative analysis of the BJTs thermal instabiliQ over a wide power range, even in the apparent SOA of the device. Also, this method can predict and evaluate SOA with respect to emitter ballast resistance and current crowding.