INFLUENCE OF DX CENTERS AND SURFACE-STATES ON DELTA-DOPED HIGH-ELECTRON-MOBILITY TRANSISTOR PERFORMANCE

The roles of DX centers and surface states associated with the n-AlGaAs layer of delta-doped AlGaAs/GaAs high-electron-mobility transistors have been investigated by employing a two-dimensional, self-consistent ensemble Monte Carlo simulation. It is found that both DX centers and surface states degrade device performance, particularly as gate-to-source voltage increases. This degradation is manifested largely through reduced channel electron concentration, increased intervalley scattering, and enhanced real-space transfer. Of the two defect states, DX centers have more detrimental influence on drain current and transconductance.