GaAsの格子欠陥におよぼす熱処理効果

抄録

The etch pit density was measured along the ‹111› axis in an N-type GaAs crystal annealed at 900°C under excess arsenic pressure ranging from 20 to 4000 Torr. After annealing, many new etch pits appeared just around the original dislocations and the maximum density was observed in the inside of the crystal. The density of an etch pit which appeared due to annealing increased with the decrease of excess arsenic pressure. From these results, it is supposed that As vacancies increased due to annealing coagulate around the original dislocations, thus forming new large defects. It is also suggested that new defects form dislocation loops because new etch pits appear and vanish in pairs during the etching of a specimen. At a higher arsenic pressure than 80 Torr, Ga vacancies, As interstitials and their complexes with other defects may be one of the factors of making new defects.