Simulation of Field-Plate Effects on Surface-State-Related Lag and Current Slump in GaAs FETs

摘要

Two-dimensional transient analysis of field-plate GaAs MESFETs is performed in which surface states are considered. Quasi-pulsed current-voltage curves are derived from the transient characteristics. It is shown that drain lag and current slump due to surface states are reduced by introducing a field plate because fixed potential at the field plate leads to reducing trapping effects by the surface states. Dependence of lag phenomena and current slump on field-plate length and SiO2 passivation layer thickness is also studied, suggesting that there are adequate values of field-plate length and SiO2 layer thickness to reduce current slump and also to maintain high-frequency performance of GaAs FETs.