Abstract:
Diffusion of krypton in poly and single crystalline silicon carbide is investigated and compared with the
previously obtained results for xenon, which pointed to a different diffusion mechanism than observed for
chemically active elements. For this purpose 360 keV krypton ions were implanted in commercial 6H-SiC
and CVD-SiC wafers at room temperature, 350 °C and 600 °C. Width broadening of the implantation profiles
and krypton retention during isochronal and isothermal annealing up to temperatures of 1400 °C was determined
by RBS-analysis, whilst in the case of 6H-SiC damage profiles were simultaneously obtained by α-
particle channelling. Little diffusion and no krypton loss was detected in the initially amorphized and eventually
recrystallized surface layer of cold implanted 6H-SiC during annealing up to 1200 °C. Above that
temperature thermal etching of the implanted surface became increasingly important. No diffusion or krypton
loss is detected in the hot implanted 6H-SiC samples during annealing up to 1400 °C. Radiation damage
dependent grain boundary diffusion is observed at 1300 C in CVD-SiC. The results seem to indicate, that
the chemically inert noble gas atoms do not form defect-impurity complexes, which strongly influence the
diffusion behaviour of other diffusors in silicon carbide.
