Radiation Effects of 5MeV Proton on Wet Oxidation SiO2/4H-SiC MOS Capacitor

Abstract

In this paper, the impact of protons irradiation on SiO 2 /4H-SiC MOS capacitors fabricated by high temperature wet oxidation have been investigated for the first time. SiO 2 /4H-SiC MOS capacitors were irradiated by 5MeV protons with different fluences. The devices electrical performances have been characterized in detail before and after the proton irradiation. Unlike for reported radiation response of dry oxidation SiO 2 /4HSiC MOS capacitors, it is very interesting that significantly higher net trapped negative charge density were observed in irradiated wet oxidation SiO 2 /4H-SiC MOS capacitors, leading to a positive flat-band voltage shift. And it is also found that the SiO 2 /4H-SiC interface quality was improved and the interface states density (D it ) reduced by about 90% after protons irradiation. By using high frequency C-V measurement, and SRIM simulation, we conclude that the electron traps introduced in SiO 2 and the deep level interface traps introduced in 4H-SiC epitaxial layer may be the main reasons for the change of SiO 2 /4H-SiC MOS capacitors electrical characteristic.