KINETIC-STUDY OF SILICON-NITRIDE GROWTH FROM DICHLOROSILANE AND AMMONIA

The model of silicon nitride film deposition in a batch furnace from d ichlorosilane (SiH2Cl2;DCS) and ammonia (NH3) is presented. The gas-ph ase and surface reaction rates of DCS are estimated from thickness pro files along the gas stream direction, and surface reaction and DCS dec omposition are found to be of Langmuir and Lindemann types, respective ly. It means that at a normal deposition temperature (similar to 1000 K); some DCS molecules adsorb directly on the Si surface while others decompose into a more reactive intermediate, SiCl2. At higher temperat ures, the reverse reaction of DCS decomposition and the subsequent rea ction of SiCl2 with NH3 may play significant roles. Using the present reaction rates, we estimate the film thickness profiles across a 12-in ch wafer.