AlGaN/GaN/GaN:C Back-Barrier HFETs With Breakdown Voltage of Over 1 kV and Low $R_{scriptscriptstyle{rm ON}} times A$

摘要

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-$muhbox{m}$ gate–drain separation on semi-insulating SiC and a 7-$muhbox{m}$ gate–drain separation on $n$-SiC exhibit 938 V and 0.39 $hbox{m}Omega cdot hbox{cm}^{2}$ and 942 V and 0.39 $hbox{m} Omega cdot hbox{cm}^{2}$, respectively. A power device figure of merit of $sim!!hbox{2.3} times hbox{10}^{9} hbox{V}^{2}/Omega cdot hbox{cm}^{2}$ was calculated for these devices.