Hole Injection Effect and Dynamic Characteristic Analysis of Normally Off p-GaN HEMT with AlGaN Cap Layer on Low-Resistivity SiC Substrate

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

doi:10.3390/mi13050807

Hole Injection Effect and Dynamic Characteristic Analysis of Normally Off p-GaN HEMT with AlGaN Cap Layer on Low-Resistivity SiC Substrate

Micromachines (Basel). 2022 May 22;13(5):807. doi: 10.3390/mi13050807.

Authors

Hsiang-Chun Wang^{1

2

3}, Chia-Hao Liu³, Chong-Rong Huang³, 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

A p-GaN HEMT with an AlGaN cap layer was grown on a low resistance SiC substrate. The AlGaN cap layer had a wide band gap which can effectively suppress hole injection and improve gate reliability. In addition, we selected a 0° angle and low resistance SiC substrate which not only substantially reduced the number of lattice dislocation defects caused by the heterogeneous junction but also greatly reduced the overall cost. The device exhibited a favorable gate voltage swing of 18.5 V (@I_GS = 1 mA/mm) and an off-state breakdown voltage of 763 V. The device dynamic characteristics and hole injection behavior were analyzed using a pulse measurement system, and Ron was found to increase and V_TH to shift under the gate lag effect.

Keywords: VTH shifting; dynamic Ron; hole injection; normally-off; p-GaN E-mode HEMT.

Grants and funding

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