The effects of deposition variables on deposition rate in the chemical vapour deposition of silicon nitride

Abstract

Amorphous Si 3N 4 was deposited by a chemical vapour deposition technique using an SiCl 4, NH 43 and H 2 gaseous mixture onto a silicon single crystal. The effects of deposition time, substrate temperature, gas flow rate, system pressure and partial pressure of reactant gases on the deposition rate were investigated. The metal-insulator-semiconductor (MIS) structure was fabricated by evaporating gold on Si 3N 4 to measure the charges stored in the interface between the insulator and silicon. The charges were determined for different deposition temperatures from capacitance-voltage plots. The experimental results indicate that the growth of Si 3N 4 is a thermally activated process in this experimental condition. It is calculated that the apparent activation energy is about 33 kcal mol -1 below the deposition temperature of 1100 °C. The homogeneous reactions in the gas phase are promoted when the total pressure is increased. At pressures above 300 Torr, deposition rates are decreased because the reactant gases are depleted because of the homogeneous reaction. The charges stored in the MIS structure are found to be larger at lower deposition temperatures.