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

Abstract

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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text{D}}$ </tex-math></inline-formula> ) exceeds 20 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{DS}} = -50$ </tex-math></inline-formula> V and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{GS}} = -20$ </tex-math></inline-formula> 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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\mathrm{\scriptstyle{ON}}}\text{S}$ </tex-math></inline-formula> ) of 2.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega \cdot \text{cm}^{2}$ </tex-math></inline-formula> , 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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> 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.