Crystallization of an amorphous layer in P+-implanted 6H-SiC studied by monoenergetic positron beams

Depth distributions and species of defects were determined from measurements of Doppler broadening spectra of annihilation radiation and lifetime spectra of positrons for 6H-SiC implanted with 200 keV P+ at a dose of 1×1015 cm−2. The annealing behavior of an amorphous layer was divided into four stages. Stages I (100–500 °C) and II (500–1100 °C) were identified as the relaxation of amorphous networks and the agglomeration of open spaces owing to rearrangements of atoms, respectively. In states III (1100–1500 °C) and IV (1500–1700 °C), corresponding to the recrystallization of the amorphous layer, the mean size of the open volume of defects decreased with increasing annealing temperature; these defects were identified as open spaces adjacent to extended defects. Vacancy-type defects were found in the subsurface region (<100 nm) at high concentration even subsequent to an annealing at 1700 °C. The annealing behavior of defects in the specimens irradiated at elevated temperatures is also discussed.