Experimental and Monte Carlo analysis of near-breakdown phenomena in GaAs-based heterostructure FETs

We present experimental end theoretical data related to the impact ionizati on in the near-breakdown regime of AlGaAs/InGaAs pseudomorphic high-electro n-mobility transistors (P-HEMTs) and AlGaAs/GaAs heterostructure field effe ct transistors (HFETs). Room-temperature electroluminescence spectra of P-H EMT exhibit a maximum around the InGaAs energy gap (1.3 eV). Two peaks have been observed for the HFETs. These experiments are interpreted by means of Monte Carlo simulations The most important differences between the two dev ices are found in the hole distribution. While the holes in the P-HEMT are confined in the gate-source channel region and responsible for the breakdow n, they are absent from the active part of the HFET. This absence reduces t he feedback and improves the on-state breakdown voltage characteristics.