Transmission electron microscopy and high-resolution electron microscopy studies of structural defects induced in 6H α-SiC single crystals irradiated by swift Xe ions

Abstract

Single crystals of 6Hα-SiC, p type, were irradiated with 5·5GeV Xe ions supplied by GANIL close to the 〈0001〉 crystal axis with fluences up to 10¹⁵ Xe cm⁻². After irradiation the colour of the crystals changed in the irradiated zone. Transmission electron microscopy observations of samples which had been irradiated and then annealed at 1373 K revealed the presence of loops lying in basal and prismatic planes. Basal faults have an interstitial character with a Burgers vector of the type ¹/₆〈0001〉. Contrast analyses as well as high-resolution electron microscopy observations allowed us to propose a geometrical model for the new defects observed in prismatic planes of the 6H polytype. These prismatic loops are the consequence of interstitial precipitation in {1012} pyramidal planes; the fault plane has a ‘zigzag’ configuration and a Burgers vector of the type ¹/₁₈〈8081〉.