OBSERVATION OF 5 ADDITIONAL THERMAL DONOR SPECIES TD12 TO TD16 AND OF REGROWTH OF THERMAL DONORS AT INITIAL-STAGES OF THE NEW OXYGEN DONOR FORMATION IN CZOCHRALSKI-GROWN SILICON

Thermal donors (TDs) are generated in Czochralski-grown silicon by heat treatments at temperatures around 470-degrees-C. They form a family of individual species with differing ionization energies and act as double donors (TDx0 TDx+). Up to 11 species are already known. We have identified five further effective-mass-like TD species termed TD12 to TD16. Subsequent annealing at 620-degrees-C for 30 min reduces the generated TDs by at least 2 orders of magnitude. With increasing annealing time (30-180 min), an intermediate regrowth of species TD1 to TD4 is observed in parallel with the initial formation of the so-called new oxygen donors.