THE ROLE OF ACCEPTOR DENSITY IN GAAS ALGAAS BASED QUANTUM-WELL HEMTS/

Numerical results based on a self-consistent solution of Poisson's and Schrodinger's equations for GaAs/AlGaAs quantum well HEMTs are presen ted. It is shown that varying the acceptor density in a quantum well s ignificantly affects the threshold voltage, the channel charge density , and hence the drain current. Particularly, near threshold and the su bthreshold region, for a given gate bias a change of acceptor density from similar to 10(13) to similar to 10(16) cm(-3) decreases the drain current by two orders of magnitude. For typical acceptor densities ex isting in the MBE-grown GaAs channel, a shift in the threshold voltage of 120 mV was obtained. The role of acceptor density is enhanced at i ncreasing well width. (C) 1997 Elsevier Science Ltd.