190Kおよび室温でガンマー線照射したp型ゲルマニウムの焼鈍

Annealing of radiation induced defects in p-type germanium was studied by measuring minority carrier lifetime. The activation energy and the reaction order of the higher temperature stage ( 130℃-180℃) were dependent on the irradiation temperature. These values for indium-doped samples irradiated at room temperature were 1.04 eV and 2nd order, and those for the sample irradiated at 190 K were 1.33 eV and 1st order. The similar behaviour was also observed in gallium-doped samples. The higher temperature stage was larger and the lower temperature stage (20℃-60℃) was smaller for room temperature irradiation than irradiation at 190 K. A recombination center located at 0.06 eV above the valence band was removed through the intermediate temperature stage (80℃-125℃) and the higher temperature stage. The shallow trap, which was formed at 0.13 eV below the conduction band by the annealing to 60℃, disappeared in the intermediate temperature stage. Deep trap grew up simultaniously at the expense of the shallow trap and was not affected by further annealing to 200℃.