Effects of Electron Irradiation on Defects of 4H-SiC MOS Materials
4H-SiC metal-oxide-semiconductor(MOS)-based devices appear to worse electrical performance when exposed to electron irradiation,owing to the production of material defects.This study demonstrates an analysis of defect evolution of 4H-SiC MOS capacitors with the simplest structure,subjected to a series dose of electron irradiation with 10 MeV electron beam,including 30,50,100,500,1 000 kGy.Deep level transient spectroscopy(DLTS)test and capacitance-voltage(C-V)measurement were used to obtain defects information among MOS samples pre-and post-irradiation.DLTS results present that a low dose of irradiation causes no evident impact on defect evolution near and at the 4H-SiC/SiO2 interface,whereas a high dose of irradiation makes a defect configuration of carbon interstitial dimer defect evolve into another more stable one at a deeper energy level.C-V curves show that different irradiation doses lead to different negative shift degrees of flat-band voltage.This is considered to be resulted from multiple factors,including oxygen vacancies in the SiO2 layer and defects near and at the 4H-SiC/SiO2 interface.This work might be helpful for the development and optimization of 4H-SiC MOS fabrication with respect to anti-irradiation performance.
万方数据
维普
