**A Novel GaN Metal-Insulator-Semiconductor High Electron Mobility Transistor Featuring Vertical Gate Structure**

#### **Zhonghao Sun 1, Huolin Huang 1,\*, Nan Sun 1, Pengcheng Tao 1, Cezhou Zhao 2 and Yung C. Liang 3**


Received: 3 November 2019; Accepted: 29 November 2019; Published: 5 December 2019

**Abstract:** A novel structure scheme by transposing the gate channel orientation from a long horizontal one to a short vertical one is proposed and verified by technology computer-aided design (TCAD) simulations to achieve GaN-based normally-o ff high electron mobility transistors (HEMTs) with reduced on-resistance and improved threshold voltage. The proposed devices exhibit high threshold voltage of 3.1 V, high peak transconductance of 213 mS, and much lower on-resistance of 0.53 m Ω·cm<sup>2</sup> while displaying better o ff-state characteristics owing to more uniform electric field distribution around the recessed gate edge in comparison to the conventional lateral HEMTs. The proposed scheme provides a new technical approach to realize high-performance normally-o ff HEMTs.

**Keywords:** wide-bandgap semiconductor; high electron mobility transistors; vertical gate structure; normally-o ff operation; gallium nitride
