VACANCIES AND VACANCY-OXYGEN COMPLEXES IN SILICON - POSITRON-ANNIHILATION WITH CORE ELECTRONS

Various point defects in silicon are studied theoretically from the po int view of positron annihilation spectroscopy. Properties of a positr on trapped at a single vacancy, divacancy, vacancy-oxygen complexes (V On), and divacancy-oxygen complex are investigated. In addition to the positron lifetime and positron binding energy to defects, we also cal culate the momentum distribution of annihilation photons (MDAP) for hi gh moments, which has been recently shown to he a useful quantity for defect identification in semiconductors. The influence of atomic relax ations around defects on positron properties is also examined. Mutual differences among the high momentum parts of the MDAP for various defe cts studied are mostly considerable, which can be used for the experim ental defect determination. [S0163-1879(98)03039-2].