本論文主要是針對薄膜電晶體通道層中的微晶矽薄膜性質來進行探討。利用電漿蝕刻的物理變化，來觀察微晶矽薄膜表面變化，與對電晶體特性的影響。由於蝕刻完成之後，微晶矽所剩餘的厚度與表面粗糙度會影響到電晶體的電性好壞，故蝕刻速率的時間控制變得十分的重要。若以做為日後業界量產的機台而言，當機台的玻璃尺寸愈大，蝕刻完後的薄膜均勻度與量產速度亦為考慮的重點，故各項蝕刻參數的設定上便顯得格外的重要。

本研究以電漿蝕刻系統（Plasma Etch, PE）來做為蝕刻的主要機台。並利用PECVD 以SiH4/H2氣體流量比為100:1沈積而成的微晶矽薄膜，於320x400mm的TFT級用玻璃上來做為此次實驗的樣本，籍由改變機台的蝕刻參數，如SF6的氣體流量、射頻功率的大小、腔體壓力、蝕刻時間等製程參數，分別對樣本來進行蝕刻的動作，並透過掃描式電子顯微鏡、原子力顯微鏡等儀器，來分析這些參數對微晶矽蝕刻均一性、表面粗糙度及蝕刻速率的影響。並以較佳的蝕刻參數製成實體的電晶體模型，進行電性量測來觀察轉移特性曲線與輸出特性曲線的變化，進行相關的探討。

The subject of paper is in connection with microcrystalline characteristic of thin film transistor. The author operates plasma etching’s physical changing and to survey the face changing of microcrystalline characteristic in addition to survey that it takes an influence to thin film transistor. After etching, microcrystalline’s thickness and the roughness of microcrystalline’s face will be influence the electrical characteristic ability. The most important of all is to operate the time of etching rate. It will be to make use of machines for manufacture. If the glasses of machines more big the uniformity and rate of quantity reproduce have greater important. Formed into a sum, the etching parameter import to manufacture.

The research used the microcrystalline characteristic which made with plasma etch and PECVD for SiH4/H2 gas flow rate 100:1 The matter which subsides to the bottom of 320x400mm TFT degree glasses. The author operates Etching rate . For example, SF6 gas flow rate、RF power、pressure、time. Let each sample respectively perform their duty. Not as long as, the author through scanning electronic microscope and atomic force microscope to analyze uniformity、the roughness of face and etching rate of microcrystalline characteristic. The author takes the best parameter to make thin film transistor modal and to survey Id-Vg Current and Id-Vd Curve that were through electrical characteristic test.

摘要……………………………………………………………………… I
謝誌……………………………………………………………………… III
目次……………………………………………………………………… IV
表次……………………………………………………………………… VI
圖次……………………………………………………………………… VII

第一章 緒 論…………………………………………………………… 1
1-1 研究背景與動機……………………………………………………… 1
1-2 研究目的……………………………………………………………… 2
1-3 名詞解釋……………………………………………………………… 3

第二章 理論分析與文獻探討…………………………………………… 5
2-1 矽的固體形式………………………………………………………… 5
2-1-1 微晶矽薄膜特性……………………………………………… 6
2-1-2 微晶矽薄膜的製作方法…………………………………… 11
2-2 薄膜電晶體…………………………………………………………… 12
2-2-1 薄膜電晶體的製作………………………………………… 13
2-2-2 薄膜電晶體的動作原理…………………………………… 15
2-2-3 薄膜電晶體的特性………………………………………… 18
2-3 電漿簡介與應用……………………………………………………… 20
2-3-1 電漿形成之原理……………………………………………… 23
2-3-2 電漿蝕刻中的基本物理及化學現象………………………… 24
2-3-3 電漿蝕刻機制………………………………………………… 26
2-3-4 電漿蝕刻參數………………………………………………… 27
2-3-5 電漿蝕刻設備………………………………………………… 31
2-4 儀器原理……………………………………………………………… 32
2-4-1 原子力顯微鏡………………………………………………… 32
2-4-2 頻譜式橢圓偏光儀…………………………………………… 34
2-4-3 場發射掃描式電子顯微鏡…………………………………… 37

第三章 實驗方法與步驟………………………………………………… 39
3-1 實驗流程……………………………………………………………… 39
3-2 蝕刻系統設備與環境………………………………………………… 40
3-3 實驗試片準備………………………………………………………… 41
3-4 微晶矽薄膜蝕刻的條件……………………………………………… 42
3-5 薄膜特性量測………………………………………………………… 46

3-5-1 微晶矽薄膜厚度量測………………………………………… 46
3-5-2 薄膜表面粗糙度分析………………………………………… 47
3-5-3 電晶體的膜厚量測與蝕刻形貌……………………………… 48
3-6 微晶矽薄膜電晶體製作……………………………………………… 49
3-7 電晶體的電性量測…………………………………………………… 50

第四章 結果與討論……………………………………………………… 52
4-1 微晶矽薄膜樣本分析………………………………………………… 52
4-2 蝕刻參數對微晶矽薄膜的影響……………………………………… 54
4-2-1 蝕刻時間對微晶矽薄膜的影響…………………………… 54
4-2-2 SF6氣體流量對微晶矽薄膜影響………………………… 57
4-2-3 O2氣體流量對微晶矽薄膜影響…………………………… 60
4-2-4 蝕刻壓力對微晶矽薄膜影響……………………………… 63
4-2-5 射頻功率對微晶矽薄膜影響……………………………… 66
4-2-6 電極間距對微晶矽薄膜影響……………………………… 69
4-3 微晶矽電晶體分析…………………………………………………… 75

第五章 結論與未來研究………………………………………………… 79
5-1 結論…………………………………………………………………… 79
5-2 未來研究……………………………………………………………… 79

參考文獻…………………………………………………………………… 80

1. Donald A. Neamen, ”Semiconductor Physics & Devices”, IRWIN, 2nd ed., 1981, p. 3.
2. I. Chun Cheng and S. Wagner, “Hole and electron field-effect mobilities in nanocrystalline silicon deposited at 150℃”, Applied Physics Letter, 80 (400), 2002.
3. C. H. Lee, A. Sazonov, A. Nathan, J. Robertson, “Directly deposited nanocrystalline Silicon thin-film transistors with ultra high mobilities”, Applied Physics Letter, 89 (252101), 2006.
4. Sigurd Wagner, Helena Gleskova, I-Chun Cheng and Ming Wu, “Silicon for thin-film transistors”, Thin Solid Films, 430, 2003, pp. 15–19.
5. B. B. Jagannathan, R. L. Wallace, and W. A. Anderson, “Structural and electrical properties of thin microcrystalline silicon films deposited by an electron cyclotron resonance plasma discharge of 2% SiH4/Ar further diluted in H2”, Journal of Vacuum Science and Technology A, 16 (5), 1998, pp. 2751-2756.
6. J. Meier, R. Fluckiger, H. Keppner, and A. Shah, “Complete microcrystalline p-i-n solar cell-Crystalline or amorphous cell behavior”, Applied Physics Letters, 65, 1994, p. 860.
7. D.L. Staebler and C.R. Wronski, “Reversible conductivity changes in discharge-produced amorphous Si”, Applied Physics Letters, 31, 1997, pp. 292-294.
8. K. Tanaka, “Glow-Discharge Hydrogenated Amorphous Silicon”. KTK Scientific Publishers, 1989.
9. Lihui Guo, Michio Kondo, Makoto Fukawa, Kimihiko Saitoh And Akihisa Matsuda, “High Rate Deposition Of Microcrystalline silicon Using Conventional Plasma-Enhance Chemical Vapor Deposition ,” Japan Journal of Applied Physics, 37, 1998, pp.1116-1118.
10. H. Shirai, D. Das, J. Hanna,”A novel preparation technique for preparing hydrogenated amorphous silicon with a more rigid and stable Si network”, Applied Physics Letters, 59 (9), 1991, p.1096.
11. J. Bailat, E. Vallat-Sauvain, L. Feitknecht, C. Droz, and A. Shah, J. Appl. Phys. 93 (9),2003 ,p. 5727.
12. MM. A. Shah, J. Faist, A Perret, B. Rech, H. Schade, M. Vanecek, “Thin film microcrystalline silicon layers and solar cells: microstructure and electrical performance”, University of Neuchate, 2003, pp. 91.
13. P. G. LeComber, W. E. Spear, and A. Ghaith, “Amorphous Silicon Field-Effect Device and Possible Application,” Electronics Letter, 15, 1979, pp. 179-181.
參考文獻
14. 吳炳昇，電子發展月刊，158期，1991，p. 59.
15. 紀國鐘，鄭晃忠，液晶顯示器技術手冊，台灣電子材料與元件協會， 5， 2002.
16. Toshihisa Tsukada, "TFT-LCD Liquid-Crystal Display Addressed By Thin-Film Transistors", Japanese Technology Revies,1996 , pp57-63.
17. M. Shur, M. Jacunski, H. Slade and M. Hack, “Analytical Models for Amorphous and Polysilicon Thin Film Transistors for High Definition Display Technology”, The Journal of the Society for Information Display, 3 (4), 1995, p. 223.
18. H. Miyashita and Y. Watabe, “Dependence of thin film transistor characteristics on the deposition conditions of silicon nitride and amorphous silicon”, IEEE Transaction on Electron Devices, 41 (4), 1994, p.499.
19. M. J. Powell, “The physics of amorphous-silicon thin-film transistors”, IEEE Transaction on Electron Device, Electron Devices, 36 (12), 1989, p.2753.
20. J. W. Tsai, F. C. Luo and H. C. Cheng, “Smart Materials, Structures, and Integrated Systems”, SPIE Proceeding Conference, 3241, 1998, p. 157.
21. 龍柏華，何教恆， “乾蝕刻製程暨機台原理簡介”，光連雙月刊，53，2004.
22. Stephen A. Campbell, "The Science and Engineering of Microelectronic Fabrication", Oxford University Press, 1996, pp. 259-263
23. Brian Chapman, “Glow Discharge Process: Sputtering and Plasma Etching”, Whiley-Interscience, 1980.
24. T. Dylla, F. Finger and E. A. Schiff, “Hole drift-mobility measurements in microcrystalline silicon”, Applied Physics Letters, 87, 2005.
25. 羅吉宗，薄膜科技與應用，全華科技，2005.
26. T.E.L., ”FPD Etching System Training Textbook”, Tokyo Electron Limited, 2002.
27. A. A. Kovalevskii, V. S. Malyshev, V. V. Tsybul’skii, and V. M. Sorokin, “Isotropic Plasma Etching of SiO2 Films”, Russian Microelectronics, 31 (5), 2002, pp. 290-294.
28. Y. Kuo K. Okajima and M. Takeichi, “Plasma processing in the fabrication of amorphous silicon thin-film-transistor arrays”, IBM Journal of Research and Development, 43 (1/2), 1999.
29. 呂登復，實用真空技術，新竹黎明書店，2002，p. 15.



30. C.-Y. WU, Y.-Y. Tsai, C.-C. Lai, C.-H. Ma, Y.-H. Chen, W.-Y. Uen, “ The Structure of Hydrogenated Microcrystalline Silicon TFTs Deposited by PECVD.”, Taiwan Display Conference, 2006.
31. R. Boylestad, L. Nashelsky, “Electronic Devices and Circuit Theory”, Prentice-Hall, 6th edition, 1978.
32. H. Zou, “Anisotropic Si deep beam etching with profile using SF6/O2 plasma”, Microsystem Technologies, 2004, pp. 603-607.
33. 洪木清，“氫化非晶矽對薄膜電晶體特性之影響”，國立台北科技大學材料及資源工程系碩士論文，2000.
34. 簡耀黌，“以PECVD成長薄膜電晶體”，中原大學電子工程學系碩士論文，2005.
35. 謝啟良，薄膜電晶體之微晶矽及氮化矽薄膜特性研究，國立中興大學碩士論文，2004.