Model for the decrease in HBT collector current under DC stress based on recombination enhanced defect reactions

Based on simplifying assumptions a model is developed to describe decreasing HBT collector current under DC bias stress. The underlying processes are recombination enhanced defect reactions (REDR), namely defect generation and defect annealing. The simplification of the derived equation under particular boundary conditions leads to a form of the Eyring relationship generally employed to describe the decrease in collector current under DC bias stress. Additionally, pulsed tests with an emitter current density of J_E=200 kA/cm² have been performed. The comparison between measured data from these tests and their fit proofs the applicability of the derived equation. Of course this can not be an evidence for the real running physical processes.