Analytic Band-to-Trap Tunneling Model Including Electric Field and Band Offset Enhancement

We present an analytic band-to-trap tunneling model developed using the open boundary scattering approach. The new model explicitly includes the effect of heterojunction band offset, in addition to the well known electric field effect. Its analytic form enables straightforward implementation into TCAD device and circuit simulators. The model is capable of simulating both electric field and band offset enhanced carrier recombination due to the band-to-trap tunneling in the depletion region near a heterojunction. Simulation results of an InGaP/GaAs heterojunction bipolar transistor reveal that the proposed model predicts significantly increased base currents, because the hole-to-trap tunneling from the base to the emitter is greatly enhanced by the emitter base heterojunction band offset. The results compare favorably with experimental observations. The developed method can be applied to all one dimensional potentials which can be approximated to a good degree such that the approximated potentials lead to piecewise analytic wave functions with open boundary conditions.