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.