Grown-in Defects in Heavily Boron-Doped Czochralski Silicon

Abstract

Grown-in defects including oxygen precipitates and voids in heavily boron-doped (HB) Czochralski (CZ) and lightly boron-doped (LB) CZ silicon crystals are reported in this paper. It was found that heavy boron-doping enhanced oxygen precipitation during high-temperature annealing. Meanwhile, it was clarified that the amount of larger crystal originated particles (COPs) decreased, while that of smaller COPs increased on as-grown HB wafers, in comparison to LB wafers. Furthermore, the COPs on the HB wafers can be more readily annihilated at relatively lower temperatures. In HB CZ silicon, the heavy boron-doping, on one hand, reduces the initial concentration of vacancies incorporated in the crystal; on the other hand, it enhances oxygen precipitation at high temperatures around 1150°C, which consumes a portion of the incorporated vacancies during crystal growth, thus further reducing the amount of vacancies contributing to void formation.