Abstract

The rapid progress in fabrication techniques and subsequent performance of electronic and optoelectronic devices has stimulated the need for models that can give physical insight and accurately represent the operation of these devices. The advances in semiconductor device modeling have been equally dramatic, with the advent of new modeling techniques and improved numerical methods. The complexity and computationally intensive nature of physical models for III-V semiconductor devices has meant that equivalent circuit models dominate engineering design and characterization. Equivalent circuit model element values are generally obtained by fitting the circuit dependence to measured data This has been very successful for small-signal microwave operation. In contrast, large-signal equivalent circuit models require extensive measurements over a wide range of bias conditions, signal amplitudes, embedding impedances and frequencies to obtain a reliable element values. This has led to increased interest in using physical device models that are intrinsically capable of representing DC, transient, and large-signal (nonlinear) operation. Further, the introduction of new highly efficient modeling techniques has permitted physical models to be used for computer-aided design in a predictive role, for some microwave devices (MESFETs and HEMTs).^1,2

© 1991 Optical Society of America