Low ON-Resistance (2.5 mΩ · cm2) Vertical-Type 2-D Hole Gas Diamond MOSFETs with Trench Gate Structure

Diamonds are highly favored materials in high-temperature and high-power operations owing to their excellent characteristics, and diamond p-channel field-effect transistors (p-FETs) considerably aid in the improvement of CMOS technology, providing high performance, which is essential for inverter operations. This study demonstrates a low ON-resistance (001) vertical-type two-dimensional hole gas (2-DHG) diamond metal-oxide-semiconductor field-effect transistor (MOSFET) with a trench gate structure. The active area of the device reduced after introducing a trench gate structure that can significantly improve the device integration and high-current operation. The maximum drain current density ( {I}_{\text{D}} ) exceeds 20 kA/cm2 at {V}_{\text{DS}} = -50 V and {V}_{\text{GS}} = -20 V, which is the highest value obtained for (001) vertical-type diamond MOSFETs. This vertical-type diamond trench MOSFET can obtain the lowest ON-resistance ( {R}_{\mathrm{\scriptstyle{ON}}}\text{S} ) of 2.5 \text{m}\Omega \cdot \text{cm}^{2} , which is comparable to that of SiC and GaN vertical-type n-channel FETs (n-FETs). It can be potentially used as a p-channel power FET in a complementary inverter. Furthermore, this study demonstrates that the trench contact depth to the p+ diamond substrate significantly impacts the static characteristics of a device using the ATLAS device simulation. This result significantly contributes to the improvement of the rising drain current in the low-voltage region of the vertical-type diamond FET, which can be used in the future as p-channel power devices for the next generation of complementary inverters using GaN or SiC MOSFETs as n-channels.