A self-heating model is presented to predict the high-frequency performance of AlGaAs/GaAs heterojunction bipolar transistors (HBT's) including high current and thermal effects. A base pushout effect is discussed at high current region. And in this case, the lattice temperature, the cut-off frequency and the maximum frequency versus the collector current density are achieved.

An analytical non-linear model including surface-state effect is proposed for 4H-SiC power MESFET's with which the impact of suface damage at the ungate recess region caused by the dry-etching process on the output steady-state characterization can be illustrated clearly.The model has the advantage in very simple calculations over the 2D numerical simulations, therefore suitable for process analysis of SiC power MESFET's.