Influence of the Source–Gate Distance on the AlGaN/GaN HEMT Performance

In this paper, we present Monte Carlo simulation results on the source-gate (S-G) scaling effects in GaN-based HEMTs. The results show that a downscaling of the S-G distance can improve device performance, enhancing the output current and the device transconductance. The main reason for this effect is related to the peculiar dynamic of electrons in the GaN-based HEMTs, which leads to a nonsaturated velocity regime in the source access region, even for high drain applied voltages. On the contrary, the gate-drain distance does not affect the output current within the analyzed device geometries. Based on these results, new optimization strategies for GaN HEMTs could be defined