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 1x10(15) cm(-2). The annealing behavior of an amorphous layer was divided into four stages. Stages I (100-500 degrees C) and II (500-1100 degrees 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 degrees C) and IV (1500-1700 degrees 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 degrees C. The annealing behavior of defects in the specimens irradiated at elevated temperatures is also discussed. (C) 2000 American Institute of Physics. [S0021-8979(00)01309-8].