Numerical modeling of pnpn heterostructure switches

A one-dimensional semiconductor device simulation program with current boundary conditions has been developed and applied to optical heterostructure p-n-p-n optical switches. Both avalanche effect and bandgap discontinuities are included in the model. Numerical simulation is performed to aid in design and to determine the switching parameters. The effects of light generation and carrier lifetime on current-voltage characteristics of the switches are investigated. The modeling results are studied for both InP/InGaAs and AlGaAs/GaAs devices and compared with experimental results in the latter case. Simulation and experiment agree on holding current and voltage and on high-current on-state characteristics. The limitations and simplification of the numerical model lead to a discrepancy in the low-current off-state.<>