Hydrogen annealing of grown-in voids in nitrogen-doped Czochralski grown silicon

Abstract

The effect of nitrogen doping on grown-in crystal originated particles (COPs) in Czochralski (CZ) silicon and COP annihilation during annealing in hydrogen at high temperature has been investigated. It is found that nitrogen doping leads to denser COPs in smaller sizes during CZ silicon crystal growth. Meanwhile, it is clarified that the grown-in COPs in the nitrogen-doped CZ (NCZ) silicon can be annihilated at a much lower temperature compared to those in the CZ silicon, furthermore, the denude zone (DZ) with lower COP density in NCZ silicon was much wider than that in CZ silicon. It is reasonably concluded that the nitrogen doping reduces the supersaturation of vacancies prior to the void formation and thus decreases the onset temperature of void formation, so the size of the void is smaller and the oxide films on the inner walls of the void are assumed to be thinner in NCZ silicon, compared with those in CZ silicon. Therefore, the voids in NCZ silicon can be annihilated more easily by hydrogen annealing.