A new compound, tertiarybutylbis-(dimethylamino)phosphine, ((CH.sub.3).sub.3 C)((CH.sub.3).sub.2 N).sub.2 P, is used as a precursor in forming phosphorus-containing semiconductor material by chemical vapor deposition. Tertiarybutylbis-(dimethylamino)phosphine is prepared by reacting a phosphorus trihalide, PX.sub.3, with the tertiarybutyl Grignard reagent ((CH.sub.3).sub.3 C)MgX. The resultant product is treated with lithium dimethylamide reagent LiN(CH.sub.3).sub.2. Tertiarybutylbis-(dimethylamino)phosphine is then recovered from the reaction mixture. Phosphorus-containing semiconductor materials are formed by chemical vapor deposition by means of bubbling a carrier gas through the new compound and then transporting the ((CH.sub.3).sub.3 C)((CH.sub.3).sub.2 N).sub.2 P with the carrier gas to a heated substrate. Additional elements from groups II, III, V, and VI of the periodic table are then deposited on the substrate to form the Phosphorus-containing semiconductor materials.