Flat-band voltage shift of 4H-SiC MOS capacitors induced by interface dipole layer formation at the oxide-semiconductor and oxide-oxide interfaces. (September 2021)

• Record Type: Journal Article
• Authors: Kil, Tae-Hyeon; Noguchi, Munetaka; Watanabe, Hiroshi; Kita, Koji
• Is Part Of: Solid-state electronics. Volume 183(2021)
• Publication Date: 2021-09
• Subjects: SiC -- MOS capacitor -- Dipole layer -- Flat-band voltage; Semiconductors -- Periodicals; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.sse.2021.108115
• Languages: English
• ISSNs: 0038-1101

Abstract

Highlights: There was negative shift of VFB due to the dipole layer at SiO2 /4H-SiC interface. We successfully tuned the VFB to positive direction with additional Al2 O3 layer. Al2 O3 fabrication process had no impact on the quality of SiO2 /4H-SiC interface. Abstract: The positive flat-band voltage (VFB ) shifts of 4H-SiC (0001) MOS capacitors with Al2 O3 /SiO2 dielectric layers were systematically investigated. After nitridation, there was a negative shift of VFB due to the dipole layer at the SiO2 /4H-SiC interface induced by Si-N bonds. However, with Al2 O3 layer deposition on thermally grown oxide, an additional dipole layer was formed at the Al2 O3 /SiO2 interface, which induced positive shift of VFB . Interface state density was estimated to show that the Al2 O3 fabrication process had no impact on the quality of SiO2 /4H-SiC interface.