電漿輔助化學氣相沈積（PECVD）系統為目前最主要沈積非晶矽與微晶矽薄膜的方式。在研究上希望能提昇沈積速率、提高薄膜品質與高均勻性等目標，但卻不容易同時達成，原因是腔體裡電漿的性質難以掌控，並在不同參數下電漿的性質會有許多變化，是不容易預測的。然而實驗上關於電漿裡粒子的變化很難量測與分析，所以本研究使用二維的流體模型（ESI CFD-ACE+）模擬SiH4/H2電漿。藉由模擬的方式瞭解其中電漿的基本特性與活性粒子的密度及分佈情況，並且分析在不同功率、壓力與H2稀釋比下電漿的變化。
　　在模擬的結果中，電漿裡重要活性粒子SiH2與SiH3分佈情形的差異，主要是由產生的機制不同所造成。SiH2主要是由SiH4與電子碰撞產生，SiH3則是由SiH4與H的化學反應生成佔大部分，所以粒子的分佈情形不同。進一步分析發現，由於不同的產生方式，使得SiH2與SiH3隨壓力變化的趨勢相反。SiH2隨壓力上升而下降，SiH3則隨壓力上升而上升，也使得利用OES 量測SiH*光譜強度不能正確反應SiH3粒子在壓力下的影響。
　　最後我們以SiH3通量密度來表示沈積速率在參數改變下的變化。以H/SiH3通量密度的比值代表矽薄膜結晶率的改變，並與實驗作比較，得到了相近的結果。

　　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 .

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