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Electronic properties of ZrO2 films fabricated via atomic layer deposition on 4H-SiC and Si substrates

Authors :
Xi-Rui Wang
Yu-Xuan Zeng
Jie Zhang
Wei Huang
Hong-Ping Ma
Qing-Chun Zhang
Source :
Materials Research Express, Vol 11, Iss 1, p 015902 (2024)
Publication Year :
2024
Publisher :
IOP Publishing, 2024.

Abstract

Being an important semiconductor material for high power applications, silicon carbide (SiC) faces the problems while used as a gate oxygen layer in traditional Si MOS devices. In view of this, an innovative approach was adopted in the present work to replace the conventional SiO _2 with a high-k material (ZrO _2 ) as the gate oxygen layer to investigate its effect on the electrical characteristics of the devices. In particular ZrO _2 films were deposited on Si and SiC substrates by atomic layer deposition (ALD), and Al was used as the electrode. The atomic force microscopy (AFM) microregion scan revealed a highly flat surface with R _q < 1 nm after the ALD growth of ZrO _2 layer. The sample surface analysis via x-ray photoelectron spectroscopy (XPS) suggested the presence of a small amount of ZrO _x components. According to the electron energy loss spectrum (EELS), the band gap width (E _g ) of this ALD ZrO _2 dielectric was 5.45 eV, which met the requirements for high-quality 4H-SiC-related MOS devices. The electrical properties of the samples were then studied, and the maximum breakdown voltage of the Al/ZrO _2 /SiC/Al MOS structure was obtained to be 23 V, i.e., nearly twice that of the Si substrate. As for the oxide layer, the interface defect density (D _it ) near the conduction band of the Al/ZrO _2 /SiC/Al MOS structure was only 10 ^12 eV ^−1 cm ^−2 orders of magnitude. The N _eff value (the movable charge) of the structure was also controlled at 10 ^12 cm ^−2 . Therefore, the overall performance of the ZrO _2 /SiC structure in terms of electrical properties exceeded that of the ZrO _2 /Si structure and previously reported counterparts. In this respect, the ZrO _2 /SiC MOS capacitor structure has great research potential.

Details

Language :
English
ISSN :
20531591
Volume :
11
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Materials Research Express
Publication Type :
Academic Journal
Accession number :
edsdoj.b2f58bbdb9d943d79ce4ff421438caa3
Document Type :
article
Full Text :
https://doi.org/10.1088/2053-1591/ad1e0a