Effects of field plate on surface- and substrate-related power slump in GaAs MESFETTS

Two-dimensional transient analysis of GaAs MESFETs with a field plate is performed in which surface states and substrate traps are considered. It is studied how the existence of field plate affects slow current transients (lag phenomena) and power slump (current slump) due to surface states and substrate traps. It is shown that both surface-state-related and substrate-trap-related transients and power slump are reduced by introducing a field plate. It is suggested that there are optimum values for field-plate length and insulator thickness to reduce the power slump and also to maintain high frequency performance of GaAs MESFETs.