Simulation of Removal of Surface-State-Related Lag and Current Slump in GaAs FETs

H. Hafiz, M. Kumeno, K. Horio
Shibaura Institute of Technology, JP

Keywords: GaAs FET, field plate, current slump, surface state, drain lag, gate lag

Summary:

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, indicating that the lags and current slump can be completely removed in some cases.