Improved Ion/Ioff Current Ratio and Dynamic Resistance of a p-GaN High-Electron-Mobility Transistor Using an Al0.5GaN Etch-Stop Layer

Hsiang-Chun Wang; Chia-Hao Liu; Chong-Rong Huang; Min-Hung Shih; Hsien-Chin Chiu; Hsuan-Ling Kao; Xinke Liu

doi:10.3390/ma15103503

Improved I_on/I_off Current Ratio and Dynamic Resistance of a p-GaN High-Electron-Mobility Transistor Using an Al_0.5GaN Etch-Stop Layer

Materials (Basel). 2022 May 13;15(10):3503. doi: 10.3390/ma15103503.

Authors

Hsiang-Chun Wang^{1

2

3}, Chia-Hao Liu³, Chong-Rong Huang³, Min-Hung Shih³, Hsien-Chin Chiu^{3

4}, Hsuan-Ling Kao^{3

4}, Xinke Liu²

Affiliations

¹ College of Materials Science and Engineering, Shenzhen University-Hanshan Normal University Postdoctoral Workstation, Shenzhen University, Shenzhen 518060, China.
² Key Laboratory of Optoelectronic Devices and Systems, Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
³ Department of Electronic Engineering, Chang Gung University, Taoyuan 333, Taiwan.
⁴ Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan.

Abstract

In this study, we investigated enhance mode (E-mode) p-GaN/AlGaN/GaN high-electron-mobility transistors (HEMTs) with an Al_0.5GaN etch-stop layer. Compared with an AlN etch-stop layer, the Al_0.5GaN etch-stop layer not only reduced lattice defects but engendered improved DC performance in the device; this can be attributed to the lattice match between the layer and substrate. The results revealed that the Al_0.5GaN etch-stop layer could reduce dislocation by 37.5% and improve device characteristics. Compared with the device with the AlN etch-stop layer, the p-GaN HEMT with the Al_0.5GaN etch-stop layer achieved a higher drain current on/off ratio (2.47 × 10⁷), a lower gate leakage current (1.55 × 10^-5 A/mm), and a lower on-state resistance (21.65 Ω·mm); moreover, its dynamic R_ON value was reduced to 1.69 (from 2.26).

Keywords: etch-stop layer; high selectivity ratio; normally off; p-GaN gate HEMT.

Grants and funding

This research was funded by the Ministry of Science and Technology (MOST), Taiwan, R.O.C., grant number MOST 110-2622-E-182-006; and the Chang Gung Memorial Hospital, Taiwan, R.O.C., grant number BMRP828.