Oxygen precipitation in heavily phosphorus-doped silicon wafer annealed at high temperatures

Oxygen precipitation in heavily phosphorus-doped (P-doped) Czochralski (CZ) silicon subjected to single-step annealing at high temperatures in the range of 1050–1150°C has been investigated. It was indicated that in the heavily P-doped CZ silicon there were more grown-in oxygen precipitates, thus promoting the generation of induced defects and accelerating the Ostwald ripening of oxygen precipitates during the high temperature annealing, in comparison with the control lightly P-doped CZ silicon with comparable initial oxygen concentration and thermal history. Moreover, it was found that, during the annealing at 1050°C, oxygen precipitation in the outer region about 2.5cm in width was noticeably retarded with respect to that in the inner region across the heavily P-doped CZ silicon wafer. The mechanism for the enhanced formation of grown-in oxygen precipitates and the retardation of oxygen precipitation at high temperature, as mentioned above, has been tentatively explained.