CHARGE-STATE DEPENDENCES OF POSITRON TRAPPING RATES ASSOCIATED WITH DIVACANCIES AND VACANCY-PHOSPHORUS PAIRS IN SI

Charge state dependences of positron trapping rates associated with di vacancies and vacancy-phosphorus pairs in Si have been studied by cont rolling the Fermi level systematically. The specific trapping rates of both a divacancy and a vacancy-phosphorus pair increase with an incre ase in the negative charge on them. A positively charged divacancy sho ws no detectable positron trapping. Such charge state dependences of t he positron trapping rates clearly show that the long-range Coulomb in teractions between a positron and a charged divacancy or a charged vac ancy-phosphorus pair play an important role in the trapping process.