1-kV β-Ga<sub>2</sub>O<sub>3</sub>UMOSFET with Quasi-Inversion Nitrogen-Ion-Implanted Channel
Qi Liu, Xuanze Zhou, Man Hoi Wong, Huidong Yao, Jingbo Zhou, Xiaodong Zhang, Guangwei Xu, Shibing Long
Abstract
In this work, 1-kV vertical enhancement-mode <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta- \text{Ga}_{2}\mathrm{O}_{3}$</tex> U-shaped trench gate metal-oxide-semiconductor field-effect transistors (UMOSFETs) with nitrogen-ion-implanted channel have been successfully demonstrated. The nitrogen-ion-implanted region serves as a current blocking layer (CBL) and also allows a quasi-inversion channel to form at the trench sidewall. The activation annealing temperature of the nitrogen-ion-implanted CBL was optimized to suppress the leakage current. The CBL annealed at 1150 °C exhibits better current blocking capability than its 1100 °C annealed counterpart. Based on the CBL annealed at 1150 °C, the UMOSFET exhibits an improved on-off ratio of ~ 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup>, an on-resistance of 87.6 mΩ-cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>and a remarkable breakdown voltage of 1028 V. This is the first 1-kV <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2}\mathrm{O}_{3}$</tex> MOSFET based on CBL, showing the potential <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{of}\beta-\text{Ga}_{2}\mathrm{O}_{3}$</tex> UMOSFETs with N-implanted channel for kilovolt-class applications.