PNNL

Abstract

Disorder accumulation and amorphization in 6H-SiC single crystals irradiated with 2.0 MeV Au2? ions at temperatures ranging from 150 to 550 K have been investigated systematically based on 0.94 MeV D? channeling analyses along the axis. Physical models have been applied to fit the experimental data and to interpret the temperature dependence of the disordering processes. Results show that defect-stimulated amorphization in Au2?-irradiated 6H-SiC dominates the disordering processes at temperatures below 500 K, while formation of clusters becomes predominant above 500 K. Two distinctive dynamic recovery stages are observed over the temperature range from 150 to 550 K, resulting from the coupled processes of close-pair recombination and interstitial migration and annihilation on both sublattices. These two stages overlap very well with the previously observed thermal recovery stages. Based on the model fits, the critical temperature for amorphization in 6H-SiC under the Au2? ion irradiation conditions corresponds to 501 +- 10 K.