GATE CURRENTS IN HETEROSTRUCTURE FIELD-EFFECT TRANSISTORS - CONTRIBUTION BY WARM ELECTRONS

The two-dimensional electron gas in a heterostructure field-effect tra nsistor is heated by the drain potential. The elevated electron temper ature in turn causes an increased gate current. The highest electron t emperature is reached at the drain. However, the gate-to-channel barri er is the highest at the drain, which decreases the electron transfer over the barrier. In this paper we investigate the dependence of the g ate current on lattice temperature and drain bias, and show that at hi gh drain and gate biases the largest contribution to the gate current comes from the region where the electron temperature, leading to the e lectron emission from the channel to the gate, is less than 100 degree s C larger than the lattice temperature.