Oxygen concentration in Czochralski silicon crystals depending on silicon monoxide evaporation from boron doped silicon melts

Abstract

In order to investigate heterogeneity in silicon single crystals depending on silicon monoxide evaporation from the free melt surface, several Czochralski crystals having various diameters were grown from silicon melts heavily doped with boron and its oxygen and boron concentration were examined. In cases of crystal growth from heavily boron doped silicon melts, it was found that the difference in oxygen concentration between the center part and the periphery of the crystals increases with increasing crystal diameter. On the contrary, in a case of non-doping, the radial oxygen distribution was relatively uniform in comparison to the results of crystal growth from heavily boron doped silicon melts, while boron were distributed uniformly in the silicon crystals. It could be concluded that the radial oxygen distribution in the silicon crystals is much influenced by the silicon monoxide evaporation which is activated by means of boron doping into the silicon melts.