Recrystallization of He-ion implanted 6H-SiC upon annealing

Abstract

Solid phase epitaxial growth of amorphous 6H-SiC created by 15keV He ion implantation to doses of 1.5×1016, 5×1016 and 1×1017cm−2 at room temperature (RT) followed by annealing ranging from 600°C to 900°C for 30min was investigated. The recrystallization process was investigated via cross-sectional transmission electron microscopy (XTEM). Recrystallization initially nucleates and grows at the interface between the amorphous layer and 6H-SiC substrate. In the middle of the amorphous layer, recrystallization nucleation is inhibited. Recrystallization rate is related to the implantation-induced damage and concentration of He impurity. The Fourier transformed images denote that the region of recrystallization contains 3C-SiC and 6H-SiC with different crystalline orientations. Besides, for the 1×1017cm−2 implanted sample, partial areas are kept amorphous in the damaged layer. The threshold temperature of full recrystallization of He ion-implantation-induced amorphization in 6H-SiC and the previous observations on other ions implantation, such as Ne, Ar, Xe etc is compared. The possible reasons are discussed.