LOW-PRESSURE CHEMICAL VAPOR-DEPOSITION OF TANTALUM SILICIDE

A process for the low pressure chemical vapor deposition (LPCVD) of tantalum disilicide is described. The process sequence requires the deposition of undoped polysilicon followed by the deposition of tantalum silicide in a single reactor. The chemistry involves the reaction of TaCl//5 with SiH//4 to produce a tantalum rich silicide (Ta//5Si//3), and a competing reaction of TaCl//5 with solid silicon to produce TaSi//2. The tantalum rich silicide phase reacts with the underlying polysilicon during the deposition process and during a post-deposition anneal to form the silicon saturated phase TaSi//2.