DC analysis of GaN-capped AlGaN/GaN HEMT for different gate-drain spacing

Wide band semiconductors are of great importance for high-frequency, high-power, and high-temperature applications. Out of various materials and device technologies, the AlGaN/GaN high-electron mobility transistor are the promising one. In this paper, we present the GaN-Capped AlGaN/GaN HEMT on SiC substrate and the simulation has been carried out using Sentaurus TCAD tools. The simulations result of the GaN-Capped AlGaN/GaN HEMT on SiC substrate showing the influence of upscaling and downscaling of the gate-drain spacing on the performance of AlGaN/GaN HFET on SiC substrate. The results show that the performance of the device first improved and then degraded with increase of gate-drain spacing. This is because of the non-uniform electric field distribution under the gate-drain spacing which causes a non-saturated velocity regime. This non-saturated velocity first causes the increment and then decrement in 2DEG concentration. Based on these outcomes, new optimization strategies for better performance of the device could be carried out.