Ion beam induced nanocrystallization of SiC

Ion-beam-induced crystallization (IBIC) was used to produce nanocrystals in the preamorphized region of a 6H-SiC bulk crystal. The precipitation was stimulated by high dose implantation with Al and Si at temperatures between 300 °C and 700 °C. The morphology of the nanocrystalline phase and its dependence on the implantation parameters were investigated by cross-sectional transmission electron microscopy (XTEM). Above a certain threshold dose, randomly oriented grains of 3C-SiC with almost spherical shape and mean diameters ranging from 4 to 25 nm are formed. The recrystallization is completed within a very narrow time window. Therefore, in our experiments the nucleation and growth process could not be observed directly. From the extrapolation of the kinetics of the secondary grain growth to zero time the window of suitable parameters for the observation of nucleation and primary grain growth was estimated. A critical temperature (TC 300 °C) as well as an incubation time (tI 300 s below 700°C) for the beginning of the recrystallization were found.