臺灣博碩士論文加值系統

本研究旨在探討沉積本質非晶矽之電漿在製程中對薄膜特性的影響，研究以模擬為主，再以實驗配合相互驗證，模擬藉由CFD-ACE+流體模型軟體研究SiH4/H2電漿，以了解電漿特性與活性粒子的密度及分佈情況，並且探討在不同功率與H2稀釋比下對於電漿特性和活性粒子例如H、SiH3、SiH2與高階矽烷粒子Si4H9生成量之影響。模擬第一部分使用兩種反應式模型進行模擬並比較差異，修改模型為原有模型另外再加入H物種相關反應式，模擬結果顯示修改模型的電漿特性，電子密度與電漿電位都是較低，而活性粒子密度則是相反；第二部分，使用沉積非晶矽與微晶矽電漿之參數進行模擬並比較兩者間的電漿特性差異，前者的電子密度與電漿電位與活性粒子及高階矽烷粒子都較低，可知沉積非晶矽的電漿環境會減少因高階矽烷粒子而產生的微孔洞；第三部分結果顯示電漿電位隨功率提高而上升，但不受氫氣稀釋比影響，而SiH2/SiH3通量密度比不受功率影響，但會隨著氫氣稀釋比增加而上升，提高功率與H2稀釋比則都會使Si4H9/SiH3增加，綜合以上結果沉積非晶矽薄膜之電漿使用低功率及低氫氣稀釋比能減少離子轟擊對薄膜的損害以及減少微孔洞產生的機率。
而實驗方面，使用PECVD以模擬使用的參數來沉積非晶矽薄膜，過程使用OES記錄電漿光譜，在改變H2稀釋比下，會發現單位時間HSiH*光譜變化率在較高H2稀釋比的電漿環境下提升速率較快；在薄膜微孔洞分析中，模擬與光譜分析結果都指出提高H2稀釋比會增加高階矽烷粒子密度，實驗結果中較低H2稀釋比亦有相同的變化趨勢，但是較高H2稀釋比則開始降低

The purpose of this study is to investigate the influence of the plasma property on the thin film property in intrinsic amorphous silicon thin film deposition processes. This study is major on simulation, also do the experiment mutual authentication. 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 and H2 dilution ratios in plasma. First part use two model of reaction database to simulation, the revise model is which adding some reactions of hydrogen species into the original model. The plasma properties of the revise model have lower electron density and plasma potential, whereas radicals higher than the original model. Second part is comparison plasma properties of two kind of plasma which are used to deposited amorphous silicon and microcrystalline silicon thin film. In simulation result, electron density, plasma potential, the radicals and the high-order silane species of the former are lower than the latter. This results means the environment of deposition amorphous silicon will reduce the production probability of microstructure produced by higher-order silane species. In last part simulation result, plasma potential increase as power increase, but has no correlation with the hydrogen dilution ratio. On the other hand, Si4H9/SiH3 flux ratio increase increases as power and hydrogen dilution ratio increases. Based on the above result ,using lower power and hydrogen dilution ratio will decrease the damage of ion bombardment on silicon thin film and the production probability of microstructure.
In experiment studies, optical emission spectroscopy was employed for analysis in PECVD plasma discharge for a-Si:H thin films. In different hydrogen dilution ratio condition, higher hydrogen dilution ratio the have higher time variant H/SiH* increase rate. In microstructure study, simulation and OES analysis result shows same trend that density of high-order silane species increase while hydrogen dilution ratio increase. The experiment result at lower hydrogen dilution ratio also shows the same trend whereas decrease at higher hydrogen dilution ratio.

摘要 i
Abstract ii
誌謝 iv
目錄 vi
表目錄 ix
圖目錄 x
第一章 引言 1
§1.1 研究動機 2
§1.2 研究目的 3
第二章 文獻回顧 4
§ 2.1 矽薄膜成長機制 4
§ 2.2 電漿模擬文獻回顧 7
§ 2.3 光學放射光譜儀(Optical Emission Spectroscopy, OES) 11
§ 2.4 異質接面矽薄膜太陽能電池 12
§ 2.5 結論 17
第三章 基本原理 18
§ 3.1平行板電容耦合電漿源(Capacitively Coupled Plasma, CCP) 18
§ 3.2矽烷/氫氣電漿之化學反應 19
§ 3.3電漿光譜原理 22
第四章 模擬模型與研究方法 24
§4.4 研究方法 24
4.4.1統御方程式 – 電子 25
4.4.2統御方程式 – 離子、中性粒子 26
4.4.3 統御方程式 – 電磁場 28
4.4.4 邊界條件 29
§4.1 軟體介紹 31
§4.2 模擬幾何結構 31
§4.3 氣體反應式 32
第五章 模擬結果與討論 37
§5-1 不同模型對電漿特性的影響 37
5.1.1 電漿特性的差異 39
5.1.2 新增反應式對成膜粒子的影響 41
§ 5.2 成長非晶矽與微晶矽之電漿的電漿特性差異 51
5.1.1電漿電位的差異 52
5.1.2鍍膜粒子密度與通量密度的差異 53
§5.3輸入功率影響 61
5.3.1輸入功率對平均電漿電位的影響 61
5.3.2 輸入功率對鍍膜粒子密度與通量密度的影響 63
§5.4 氫氣稀釋比影響 71
5.4.1氫氣稀釋比對平均電漿電位的影響 71
5.4.2氫氣流量比對鍍膜粒子密度與通量密度的影響 73
第六章 實驗設備與研究方法 81
§ 6.1研究方法 81
§ 6.2實驗流程 81
§ 6.3實驗設備與分析方法 83
第七章 實驗結果與討論 90
§ 7.1 實驗條件 90
§ 7.2 SiH4/H2電漿放射光譜強度變化分析 91
§ 7.3薄膜鈍化效果分析 93
7.3.1矽晶片表面磊晶與OES-ratio(Hα/SiH*)之關聯性 93
7.3.2高階矽烷粒子與OES-ratio(Hβ/ Hα),H2 fulcher之關聯性 99
第八章 結論 101
Reference 103
附錄A 107
附錄B 113
附錄C 121

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