Peculiarities of Gate Design and Influence on PHEMT Characteristics

Dependence of pHEMT drain current on gate recession (etching depth of heteroepitaxial structure) is investigated. Also the dependence of specific transconductance on gate bias for pHEMTs with various initial drain current are presented. Relation between the level of drain current left before gate evaporation, transconductance and gate recession proceeding from features and physics of pHEMT is established. The influence of initial drain current magnitude on transistor microwave parameters is established. Thus, achievement of high microwave parameters of the device is possible provided the optimal choice of initial drain current proceeding from layer configuration of semiconductor structure