The annealing of defects in proton-bombarded bulk 6H- and 4H-type material was investigated by using positron lifetime spectroscopy and Doppler-broadening measurements. The experiments were performed on N-doped (n-type) or Al-doped (p-type) crystals, and on semi-insulating samples. In n-type material, the bombardment-induced defects annealed out in 4 stages: 150, 350, 750 and higher than 1000C. The magnitudes of the annealing stages depended upon the proton fluence. In p-type material, the increase in the positron parameters after proton bombardment was smaller, and a different annealing behaviour was observed after the first annealing stage at about 150C. The semi-insulating samples did not exhibit an annealing stage at 1000C.

Vacancy-Type Defects in Proton-Irradiated 6H- and 4H-SiC - a Systematic Study with Positron Annihilation Techniques W.Puff, A.G.Balogh, P.Mascher: Materials Science Forum, 2000, 338-342, 969-72