High Breakdown Voltage P-GaN Gate HEMTs With Threshold Voltage of 7.1 V

In this study, we proposed an enhanced mode P-GaN/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) by combining thermal oxidation treatment of P-GaN with atomic layer deposition (OTALD) prior to gate metal deposition. Due to the thermal oxidation treatment, a smooth oxide interlayer between P-GaN and Al<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathbf {{2}}}$ </tex-math></inline-formula>O<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathbf {{3}}}$ </tex-math></inline-formula> is formed. Compared with the device without treatment, the P-GaN gate HEMTs with OTALD present increased threshold voltage significantly from 1.8 V to 7.1 V and improved gate breakdown voltage from 18.9 V to 26.9 V. Additionally, the devices maintained a high on/off current ratio above <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{\mathbf {{8}}}$ </tex-math></inline-formula> and a further improvement in off-state breakdown voltage from 1315 V to 1980 V. The record high threshold voltage and breakdown voltage make this technology promising for widespread application in P-GaN power devices.