Study on thermodynamics and kinetics of chemical vapor deposition of silicon nitride

The thermodynamics and kinetics methods had been applied to study the effects of the deposition temperature, the reaction gas ratio and the dilution gas on Si3N4 formation in the SiCl4-NH3-H2 system. The studies revealed that raising the deposition temperature would accelerate the chemical reaction and increase Si3N4 yield below 1400 K, higher temperature prompted the side reactions. With the increase of NH3 concentration, the content of Si3N4 in the reaction products also increased. As the diluent gas, H2 could accelerate the reaction and the deposition of Si3N4. However, the excess dilution gas would carry away the reaction gas and inhibit the reaction. The comprehensive effect of temperature and gas ratio on Si3N4 deposition were also analyzed by the three-dimensional figures. Finally, the optimal conditions for Si3N4 preparation were suggested.