LPCVD of Silicon Nitride Films From Hexachlorodisilane and Ammonia

Hexachlorodisilane (Si2Cl6) has been used as an alternative to dichlorosilane and silane for growth of silicon nitride films. The films were grown at a pressure of 0.7 Torr at temperatures between 450° and 850°C. Growth rate data indicates a kinetically controlled deposition with an activation energy of 29.3 kcal/mole. Growth rates are substantially higher than those obtained from SiH2Cl2 under similar conditions, and the physical properties of the films are essentially the same. At the higher growth temperatures stoichiometric Si3N4 films with no detectable chlorine can be obtained when a NH3/Si2Cl6 ratio of 60 or greater is used.