Effects of buried p-layers on substrate-trap induced phenomena in GaAs MESFETs

Abstract

We investigate the effects of buried p-layers (BP-layers) on substrate-trap induced frequency dispersion of drain conductance in GaAs MESFETs. Our experiments show that the condition of the BP-layers significantly influences their effectiveness in suppressing trap-induced low-frequency anomalies. These results can be well explained by the self-backgating model. While suppressing trap-induced phenomena, a BP-layer itself may cause current transients at higher frequencies due to parasitic capacitance increase; this is also investigated in detail.