Effects of Electron Irradiation on Defects of 4H-SiC MOS Materials

Abstract

Abstract: 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.

Key words: 4H-SiC MOS, electron irradiation, defect evolution, carbon interstitial dimer, deep level transient spectroscopy

CLC Number:

TN386.1

LIU Shuai, XIONG Huifan, YANG Xia, YANG Deren, PI Xiaodong, SONG Lihui. Effects of Electron Irradiation on Defects of 4H-SiC MOS Materials[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2024, 53(9): 1536-1541.

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