Analysis of pulsed I-V curves and power slump in field-plate GaN-based FETs

Two-dimensional transient analyses of GaN MESFETs and AlGaN/GaN HEMTs are performed in which a deep donor and a deep acceptor are considered in a buffer layer, and pulsed I-V curves are derived from them. It is studied how the existence of field plate affects buffer-related lag phenomena and power slump. It is shown that in both FETs, the power slump could be reduced by introducing a field plate, because electron injection into the buffer layer is weakened by it. The dependence on insulator-thickness under the field plate is also studied, suggesting that there is an optimum thickness of insulator to minimize the power slump.