Oxygen Precipitation in Heavily Phosphorus-doped Czochralski Silicon

Abstract

Oxygen precipitation in heavily phosphorous (P)-doped Czochralski silicon (CZ-Si) subjected to the ramping or two-step anneals was investigated. It was revealed that the grown-in oxygen precipitates exerted significant effect on oxygen precipitation behaviors and then resulted in distinctive oxygen precipitation for the wafers form various positions of the ingot. Moreover, it was found that both the seed and tang-end wafers processed significantly intense nucleation at 650 oC without the influence of grown-in oxygen precipitates. It was considered that the heavily P-doping introduced phosphorus related precipitation at 650 oC. When the annealing temperature increased, the capability for nucleation of oxygen precipitation by heavily P-doping would be gradually weakened but the one by oxygen clustering became pronounced. In this case, it was understandable that the tang-end wafer processed higher density of oxygen precipitates than the seed-end wafer at around 750 oC, while a lower one at 1000 oC.