Effects of gamma-ray irradiation on material and electrical properties of AlN gate dielectric on 4H-SiC

Xiaogang Zhu; Zhanwei Shen; Z J Wang; Zhengran Liu; Yuyang Miao; Shizhong Yue; Zhao Fu; Zihao Li; Yuning Zhang; Rongdun Hong; Shaoxiong Wu; Xiaping Chen; Jiafa Cai; Deyi Fu; Feng Zhang

doi:10.1088/1361-6528/ad3a6e

Effects of gamma-ray irradiation on material and electrical properties of AlN gate dielectric on 4H-SiC

Nanotechnology. 2024 Apr 23;35(27). doi: 10.1088/1361-6528/ad3a6e.

Authors

Xiaogang Zhu¹, Zhanwei Shen², Z J Wang², Zhengran Liu¹, Yuyang Miao¹, Shizhong Yue², Zhao Fu¹, Zihao Li¹, Yuning Zhang¹, Rongdun Hong¹, Shaoxiong Wu¹, Xiaping Chen¹, Jiafa Cai¹, Deyi Fu¹, Feng Zhang¹

Affiliations

¹ Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China.
² Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors Chinese Academy of Sciences, Beijing 100083, People's Republic of China.

PMID: 38574479
DOI: 10.1088/1361-6528/ad3a6e

Abstract

This article investigates the radiation effects on as-deposited and annealed AlN films on 4H-SiC substrates under gamma-rays. The AlN films are prepared using plasma-enhanced-atomic-layer-deposition on an n-type 4H-SiC substrate. The AlN/4H-SiC MIS structure is subjected to gamma-ray irradiation with total doses of 0, 300, and 600 krad(Si). Physical, chemical, and electrical methods were employed to study the variations in surface morphology, charge transport, and interfacial trapping characteristics induced by irradiation. After 300 krad(Si) irradiation, the as-deposited and annealed samples exhibit their highest root mean square values of 0.917 nm and 1.190 nm, respectively, which is attributed to N vacancy defects induced by irradiation. Under irradiation, the flatband voltage (V_fb) of the as-deposited sample shifts from 2.24 to 0.78 V, while the annealed sample shifts from 1.18 to 2.16 V. X-ray photoelectron spectrum analysis reveals the decomposition of O-related defects in the as-deposited AlN and the formation of Al(NO_x)_ycompounds in the annealed sample. Furthermore, the space-charge-limits-conduction (SCLC) in the as-deposited sample is enhanced after radiation, while the barrier height of the annealed sample decreases from 1.12 to 0.84 eV, accompanied by the occurrence of the SCLC. The physical mechanism of the degradation of electrical performance in irradiated devices is the introduction of defects like N vacancies and O-related defects like Al(NO_x)_y. These findings provide valuable insights for SiC power devices in space applications.

Keywords: AlN/4H-SiC; Radiation damage; high k; hysteresis; roughness.