Dislocation dynamics in heterojunction bipolar transistor under current induced thermal stress

摘要

Dislocation generation and multiplicaiton in heterojunction bipolar transistors (HBTs) under electrical bias was studied using a finite element model. This model was developed ot solve a physicla viscoplastic solic mechanics problem using a time-dependent constitutive equation relating the dislocation dynamics to plastic deformation. The dislocatiosn in HBTs are generated by the excessive stresses including thermla stress generated by the temperature change in ht edevice during operation. It was found that the dislocation generation rate at the early stage and the statonary dislocation densities depend strongly on the current density.