Abstract

This paper describes the dynamic of the current collapse phenomenon that can occur in a multifinger power HBT. The electrothermal model used is a self consistent model based on an electrical distributed Ebers Moll model coupled to a thermal subcircuit derived from Ritz vector reduction technique of 3D thermal finite element simulation. Simulation of static as well as dynamic collector current collapse for HBT has been performed and allows to optimize the ballast resistor.