Abstract
Plasma Enhance Chemical Vapor Deposition (PECVD) system is the mainly method to deposit amorphous silicon and micro-crystal film currently. It is a difficult task to enhance the deposition rate, quality of thin film and high uniformity deposition at the same time, because the quality of plasma in chamber is not easy to control. Besides, the qualities of plasma varies under different parameters, which increase the difficulty to predict them. Also, it is hard to measure and analyze the variation of particles in plasma experimentally; therefore, this study applies two dimensional fluid model in ESI CFD-ACE+ to simulate SiH4/H2 plasma. Though simulation, we can understand the basic qualities of plasma and the density and distribution of radicals, and analyze the variations of different powers, pressures and H2 dilution ratios in plasma. In the results of simulations, the different distributions of the important radicals ( SiH2 and SiH3 ) in plasma chiefly due to different production mechanisms. SiH2 is produced by the collisions between SiH4 and electrons; SiH3 is generated by the chemical reaction between SiH4 and H. With further analyzing, we realize that SiH2 and SiH3 have opposite density trend with the variation of pressure is because of different production mechanisms. In other words, with the increase of pressure, SiH2 decrease while SiH3 increase. Thus, the SiH* spectrum intensity measured by OES can't accurately response to the effects on SIH3 particles under different pressures. Finally, the change of SiH3 flux under different variation of parameters is used to represent the effect of deposition rates of thin silicon film. The ratio of H/SiH3 flux represents the variation of crystallized rate of silicon thin film. Compared with the experiment, comparative results are achieved in the simulations .