Nitrogen in Silicon

Abstract

Liquid silicon has been exposed to gaseous ambients containing varying concentrations of N₂ or NH₃. Under certain conditions, Si₃N₄ needles may be grown on the surface and into the body of the melt. The molten zone of silicon was supported between two rods of solid silicon. We have found that the concentration of nitrogen in molten silicon which is saturated with respect to silicon nitride at a temperature near the melting point of silicon is around 10¹⁹ atoms per cm³. During the freezing of the melt, Si₃N₄ precipitates from the supersaturated liquid phase. The concentration of electrically active impurity states in silicon grown from melts containing around 10¹⁹ atoms per cm³ of nitrogen is less than 10¹² atoms per cm³.