FORMATION OF DONOR CENTERS UPON ANNEALING OF DYSPROSIUM-IMPLANTED ANDHOLMIUM-IMPLANTED SILICON

The implantation of a 10(13) cm(-2) dose of 1-MeV dysprosium and holmi um ions with subsequent annealing at temperatures in the range 600-900 degrees C leads to donor center formation. The donor center concentra tion increases with increasing oxygen concentration in the starting ma terials as well as upon additional oxygen implantation. Such behavior of the activation and the donor center concentration profiles as a fun ction of the annealing temperature and oxygen concentration is observe d in Si:Dy and Si:Ho. The results show that the formation of at least two types of donor centers containing rare-earth elements and/or oxyge n atoms takes place. (C) 1998 American Institute of Physics. [S1063-78 26(98)00209-9].