A PNP-GaN Gate AlGaN/GaN HEMT with Improved Gate Characteristics

The PNP-GaN gate AlGaN/GaN high electron mobility transistor was proposed and demonstrated in this study by adding a PN-GaN diode into the p-GaN gate structure to form a PNP-GaN gate structure. The new gate structure blocks the hole injection and improves the gate reliability verified by TCAD simulations. The new PNP-GaN gate structure can reduce the electric field on the Schottky diode and redistribute the maximum electric field from the metal Schottky gate to the NP-GaN diode due to additional voltage drops. Compared to the p-GaN gate structure, the PNP-GaN gate structure exhibits a lower gate leakage current (~ 3.4 × 10⁻³ mA/mm @ VGS =10 V) and a higher gate breakdown voltage 19.8 V. Moreover, the PNP-GaN gate HEMT shows a large threshold voltage (VTH) of 2.96 V, a high on/off current ratio of 9.4