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

Depth distributions and species of defects were determined from measurement s of Doppler broadening spectra of annihilation radiation and lifetime spec tra 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 iden tified as the relaxation of amorphous networks and the agglomeration of ope n spaces owing to rearrangements of atoms, respectively. In states III (110 0-1500 degrees C) and IV (1500-1700 degrees C), corresponding to the recrys tallization of the amorphous layer, the mean size of the open volume of def ects decreased with increasing annealing temperature; these defects were id entified as open spaces adjacent to extended defects. Vacancy-type defects were found in the subsurface region (< 100 nm) at high concentration even s ubsequent to an annealing at 1700 degrees C. The annealing behavior of defe cts in the specimens irradiated at elevated temperatures is also discussed. (C) 2000 American Institute of Physics. [S0021-8979(00)01309-8].