The effect of annealing at up to 1400K, under Ar pressures of up to 1.2GPa, upon H plasma-etched and H-implanted Czochralski or float-zone single- or polycrystalline material was investigated by using secondary ion mass spectrometry, X-ray, transmission electron microscopic and photoluminescence methods. The presence of an external stress during the annealing of H-containing material resulted in the suppression of H out-diffusion, but caused The effect of annealing at up to 1400K, under Ar pressures of up to 1.2GPa, upon H plasma-etched and H-implanted Czochralski or float-zone single- or polycrystalline material was investigated by using secondary ion mass spectrometry, X-ray, transmission electron microscopic and photoluminescence methods. The presence of an external stress during the annealing of H-containing material resulted in the suppression of H out-diffusion, but caused