Ion irradiation induced bubble relaxation in SiC

Abstract

He ion irradiation at 140 keV and subsequent annealing at 1200 K were used to introduce voids in 4H-SiC. Then, 1 MeV Si ion irradiation at room temperature was used to study irradiation-induced athermal annealing. Transmission electron microscopy and channeling Rutherford backscattering spectrum analysis were used to characterize samples. Platelet-like voids were formed at the boundary of heavily damaged layer with Si ions implanted to a fluence of 1×10¹⁵ cm⁻². When Si fluence was increased to 1×10¹⁶ cm⁻², transition of platelet-like voids into large voids was observed. The study provides evidence of ion irradiation induced athermal annealing. Monte Carlo simulation of atomic displacement on the internal surface of the He bubble suggests that ballistic collision from damage cascades plays an important role in bubble relaxation.

Keywords:

• silicon carbide
• He bubbles
• ion irradiation
• athermal annealing

PACS :

• 61.72.Cc
• 61.72.Ff
• 61.72.Nn
• 61.80.Jh
• 61.82.Fk

Acknowledgements

The authors gratefully acknowledge the support from the National Natural Science Foundation of China (Grant No. 10875004) and the National Basic Research Program of China (973 program, 2010 CB832904). Lin Shao acknowledges the support from the NRC Early Career Development Grant and the support from NSF (USA) through Grants CMMI-0846835, DMR-0905142. Wei Hua acknowledges the support from the China State Scholarship Fund.