AlGaN/GaN/GaN:C Back-Barrier HFETs With Breakdown Voltage of Over 1 kV and Low RON x A

A systematic study of GaN-based heterostructure field-effect transistors with an insulating carbon-doped GaN back barrier for high-voltage operation is presented. The impact of variations of carbon doping concentration, GaN channel thickness, and substrates is evaluated. Tradeoff considerations in ON-state resistance versus current collapse are addressed. Suppression of the OFF-state subthreshold drain-leakage currents enables a breakdown voltage enhancement of over 1000 V with a low ON-state resistance. Devices with a 5-mu m gate-drain separation on semi-insulating SiC and a 7-mu m gate-drain separation on n-SiC exhibit 938 V and 0.39 m Omega center dot cm(2) and 942 V and 0.39 m Omega center dot cm(2), respectively. A power device figure of merit of similar to 2.3 x 10(9) V-2/Omega center dot cm(2) was calculated for these devices.