成功大學博碩士論文系統

簡易檢索 / 詳目顯示

回結果列表

研究生：	陳毓儒 Chen, Yu-Ru
論文名稱：	非晶矽薄膜利用準分子雷射結晶之實驗研究與有限元素的熱傳分析 Experimental and Finite Element Analysis in Excimer-Laser Crystallization of a-Si Films
指導教授：	趙隆山 Chao, Long-Sun
學位類別：	博士 Doctor
系所名稱：	工學院 - 工程科學系 Department of Engineering Science
論文出版年：	2008
畢業學年度：	96
語文別：	英文
論文頁數：	126
外文關鍵詞：	solar cell, finite element method, poly-Si, excimer laser, FMT
相關次數：	點閱：51 下載：1
分享至:	分享至facebook 分享至twitter

查詢本校圖書館目錄查詢臺灣博碩士論文知識加值系統勘誤回報

雷射退火法是目前在LCD產業，製造低溫多晶矽薄膜最普遍的方式，本研究以脈衝式KrF雷射光照射非晶矽薄膜，於數十個毫微秒(nanoseconds)的時間尺度內使矽膜加熱、融化，然後結晶為多晶矽結構。本文以a-Si薄膜及玻璃基板作為工件材料，考慮脈衝式雷射之雷射能量密度(200~500 mJ/cm2)、雷射發數(1~2 shots)與加入隔離層等因素。利用實驗實做製程及使用掃瞄式電子顯微鏡(SEM)觀察結晶狀況，並應用有限元素法模擬雷射加熱矽薄膜之暫態溫度變化，其潛熱的處理採用等效比熱法與等效比熱熱焓法。經參考文獻之實驗對比驗證，本文所建立之數值模型之溫度曲線及融化深度可預測雷射退火非晶矽薄膜達完全融化門檻(Full-Melt Threshold, FMT)之雷射控制參數，並從本文觀察雷射退火後晶粒分佈趨勢所獲得之完全融化門檻(FMT)時之實驗條件，可發現兩者所得結果一致。於多晶矽薄膜製程之研究中，本文同時提出一分光準分子方法，為利用分光鏡將單發雷射分光，其間第一發與第二發雷射之間利用光路系統延遲照射時間，於第一發雷射將a-Si薄模融化後，而正在將凝固時，再接受第二發雷射，其兩發間的延遲時間小於單部雷射之脈衝週期，同時第二發能量較小，其目的為延長晶粒凝固時間及給於成長之能量，於實驗結果也發現能有效的增加晶粒尺寸。經由本文之實驗與數值模擬結果與討論，希望有助於相關研究之設計與應用。

In the fabrication of a poly-Si film, an amorphous silicon (a-Si) thin layer on glass substrate is melted by the irradiation of a excimer laser with nanosecond duration, and then is cooled down to form the poly-Si one. In this thesis, the excimer-laser-induced crystallization of a-Si films was investigated numerically and experimentally. The basic structure is an a-Si film on a glass substrate. The control parameters are the laser intensity (200~500 mJ/cm2), the pulse number (1~2 shots) and delay time between two shots (one nanosecond). The effects of SiO2 and SiNx layers which are utilized as heat buffer zones located between the Si film and glass substrate were also studied. In this paper, a double-splitting-laser method is proposed. In the method, a laser pulse from an excimer laser is divided into two pulses by a beam splitter. The cyclic optical path is used to control the delay time of the second pulse. Optical mirrors and optical attenuators are utilized to adjust the energy density of these two laser pulses. The delay time between these two pulses is changeable and controlled in the order of nanosecond. The second pulse is applied when the Si film is solidifying after the irradiation of the first one. This could enhance the solidification time and enlarge the grain size of the poly-Si film. In the microstructure analysis of the laser-irradiated area, the critical fluences (full-melt threshold, FMT) between the partial melting and complete melting regimes can be found by applying scanning electron microscopy. The corresponding efficient two-dimensional numerical model is built to predict the critical fluences (FMT) and the transient temperature distribution during the laser processing, based on the finite element method and the efficient specific heat and the specific heat/enthalpy method used to handle the release or absorption of latent heat. The FMT’s obtained from the simulation results of the proposed model agree fairly well with those from the experimental data reported in the literature and acquired in this research. The results of this paper are expected to be helpful to the processing designers or researchers.

ABSTRACT ..................................................................................................................    i

LIST OF TABLES .......................................................................................................   vii

LIST OF FIGURES .....................................................................................................  viii

NOMENCLATURE ....................................................................................................   xii

CHAPTER ONE INTRODUCTION ………………………………………………    1

1.1 AMLCD/Thin film transistor liquid crystal display: TFT-LCDs ………….    3
1.2 Poly-Si thin-film Solar cell ……………………………………………………    5
1.3 An overview of poly-silicon technology ………………………………………    7
1.4 Research Goal .....................................................................................................   12
1.5 Organization of dissertation …………………………………………………..   14

Chapter TWO THEORETICAL MODELING .……………………………………  16

2-1 Physical model……………………………………………….…………………..  16
 2-2 Basic Assumptions ………………………………………………………………  18
 2-3 Governing equation..…………………………………………………………….  18
 2-4 Initial and boundary condition …………………………………………………  19
 2-5 Source term....…………………………………………….………………………  20

CHAPTER THREE NUMERICAL METHOD …………………………………….  22
 
3-1 Finite element method (FEM) …………………………………………………..  22
 3-2 Mesh shape and interpolation function.………………………………………...  27
3-3 Weighted residual and Galerkin methods ……………………………..............  30
 3-4 Numerical integration……………………………………………………………  34
 3-5 Element equations of temperature field ………………………………………..  36
 3-6 The latent heat ……………………………………………………………………  39
    3-6-1 Effective specific heat method .....................................................................  39
    3-6-2 Enthalpy/specific heat method ....................................................................  40
 3-7 Solution procedures ……………………………………………………………...  43

CHAPTER FOUR EXPERIMENTAL METHOD AND EQUIPMENT ..................  44
 
4-1 Excimer laser system ................................................................................................ 45
    4-1-1 KrF excimer laser machine and control mechanism .................................  45
    4-1-2 Double-splitting-laser method …………………………………………….  47
 4-2 Plating process ……………………………………………………………………  48
4-2-1 Sputter machine and working conditions ..................................................  48
    4-2-2 Plating parameters of making a-Si films for excimer laser annealing …  48
4-2-3 Plating procedures of the amorphous silicon, silica and SiNx ..................  49
 4-3 Control parameters of the laser ...........................................................................  51
    4-3-1 Different laser fluences ................................................................................  51
    4-3-2 Pulse number ................................................................................................  52
    4-3-3 SiO2 buffer layer ..........................................................................................  52
    4-3-4 SiNx buffer layer ..........................................................................................  52
    4-3-5 Different thicknesses of the amorphous silicon film .................................  53
    4-3-6 Delay time of the double-splitting-laser method …………………………  53

CHAPTER FIVE RESULTS AND DISCUSSES ……………………………………  55

5-1 Numerical experiment .........................................................................................  55
5-1-1 Energy density profile of laser ...................................................................  56
5-1-2 Mesh analysis ...............................................................................................  57
5-2 The numerical simulation and experiment results ............................................  59
    5-2-1 Different laser fluences ...............................................................................  60
    5-2-2 Laser number ..............................................................................................  65
    5-2-3 SiO2 buffer layer .........................................................................................  66
    5-2-4 SiNx buffer layer .........................................................................................  67
    5-2-5 Different thicknesses of the amorphous silicon film ...............................  67
    5-2-6 Delay time of the double-splitting-laser method ……………………….  69
5-3 Three-dimensional simulation …………………………………………………  71

CHAPTER SIX CONCLUSIONS ………………………………………………….  72

CHAPTER SEVEN CONCLUSIONS ……………………… ….………………….  76

REFERENCES ………………………………………………………………………  78

Appendix I
Three Dimensional Modeling with Finite Element Analysis …………………….   116

VITA …………………………………………………………………………………  125
                                    

[1] N. D. Young, G. Harkin, R. M. Bunn, D. J. McCulloch, and I. D. French, “The Fabrication and Characterization of EEPROM Arrays on Glass Using a Low-Temperature Poly-Si TFT Process” IEEE Transactions on Electron Devices, Vol.43, No.11, pp.1930-1936, 1996.
[2] C.H. Oh, M. Ozawa and M. Matsumura, “A Novel Phase-Modulated Excimer-Laser Crystallization Method of Silicon Thin Films” Jpn. J. Appl. Phys. Vol.37, pp.L 492-495, 1998.
[3] D. H. Choi, E. Sadayuki, O. Sugiura, and M. Matsumura, “Lateral Growth of Poly-Si Film by Excimer laser and Its Thin Film Transistor Application ” Jpn. J. Appl. Phys, Vol.33, No.1A, pp.70-74, 1994.
[4] E. Fujii, K. Senda, F. Emoto, A. Yamamoto, A. Nakamura, Y. Uemoto, and G. Kano, “A Laser-Recrystallization Technique For Silicon-TFT Integrated Circuits on Quartz Substrates and Its Application to Small-Size Monolithic Active-Matrix LCD’s ” IEEE Transactions on Electron Devices, Vol.37, pp.121-127, 1990.
[5] S.D. Brotherton, D.J. Mcculloch, J.P. Gowers, J.R. Ayres. and M.J. Trainor., “Influence of melt depth in laser crystallized poly-Si thin film transistors”J. Appl. Phys. 82, 4086 (1997).
[6] R.B. Bergmann, J. Kohler, R. Dassow, C. Zaczek. and J.H. Werner., “Nucleation and Growth of Crystalline Silicon Films on Glass for Solar Cells” Phys. Stat. Sol. (a) Vol.166, pp.587-602, 1998.
[7] Y. R. Chen and L. S. Chao, “Experimental Analysis for Low-Temperature Poly-Si Films Produced by Using The Excimer Laser Annealing Method” Mater. Sci. Forum Vols.505-507 pp. 277-282, 2006.
[8] P. H. Yeh, Master Theory, Department of Physics & Institute Physics, National Sun-Yet San University, “Study of Self-Aligned SiGe Elevated S/D poly-Si Thin Film Transtor”, 2002.
[9] N. Ibaraki, “a-Si TFT technologies for large-size and high-pixel-density AM-LCDs’”, Materials Chemistry and Physics, 43, pp. 220-226, 1996.

[10] T. Higuchi, J. Hanari, N. Nakamura, K. Mametsuka, M. Watanabe, T. Murai, R. Watanabe, M. Seiki, Azuma, Y. Hori, K. Nakamura, Y. Aoki, H. Sakurai, T. Nakazono, N. Harada, SID Ž . 00 Digest in press .
[11] J. S. Im and R. S. Sposili, MRS Bulletin. 21, pp.39, 1996.
[12] H. Ohshima, Proc. In. Con. Active Matrix Workshop, ‘‘Euro-Display’’, Birmingham, UK, edited by P. Migliorato, Sep. 30, 1996, paper WS 2/1.
[13] M. Miyasaka, T. Nakazawa, I. Yudasaka, and H. Ohshima, “TFT and Physical Properties of Poly-Crystalline Silicon Prepared by Very Low Pressure Chemical Vapour Deposition (VLPCVD)” Jpn. J. Appl. Phys., Part 1 30, pp.3733, 1991.
[14] M. Miyasaka, T. Nakazawa, W. Ito, I. Yudasaka, and H. Ohshima, “Transistor and physical properties of polycrystalline silicon films prepared by infralow-pressure chemical vapor deposition” J. Appl. Phys. 74, pp.2870, 1993.
[15] T. Aoyama, G. Kawachi, N. Konishi, T. Suzuki, Y. Okajima, and K. Miyata, “Crystallization of LPCVD Silicon Films by Low Temperature Annealing” J. Electrochem. Soc. 136, pp.1169, 1989.
[16] T. W. Little, K. Takahara, H. Koike, T. Nakazawa, I. Yudasaka, and H. Ohshima, “Low Temperature Poly-Si TFTs Using Solid Phase Crystallization of Very Thin Films and an Electron Cyclotron Resonance Chemical Vapor Deposition Gate Insulator” Jpn. J. Appl. Phys., Part 1 30, pp.3724, 1991.
[17] T. Sameshima, M. Hara, and S. Usui, “XeCl Excimer Laser Annealing Used to Fabricate Poly-Si TFT's” Jpn. J. Appl. Phys., Part 1 28, pp.1789, 1989.
[18] H. Kuriyama et al., “Enlargement of Poly-Si Film Grain Size by Excimer Laser Annealing and Its Application to High-Performance Poly-Si Thin Film Transistor”Jpn. J. Appl. Phys., Part 1 30, pp.3700, 1991.
[19] S. Friligkos, V. Papaioannou, J. Stoemenos, R. Carluccio, S. Cina, and G. Fortunato, “Structural characterization of α-Si films crystallized by combined furnace and laser annealing”J. Cryst. Growth, 182, pp.341, 1997.
[20] J. Zhao, A. Wang, M. A. Green and F. Ferrazza, “Novel 19.8% efficient ‘honeycomb’ textured multicrystalline and 24.4% monocrystalline silicon solar cell”, Appl. Phys. Lett., 73, pp.1991, 1998.

[21] Timothy J. Coutts, J. Scott Ward, David L. Young, Keith A. Emery, Timothy A. Gessert and Rommel Noufi, “Critical Issues in the Design of Polycrystalline, Thin-film Tandem Solar Cells ,” Res. Appl., Vol.11, pp.359–375, 2003.
[22]V.D. Mihailetchi, ECN, Petten, The Netherlands, 17.4% Efficiency Solar Cell
[23]Martin A. Green1, Keith Emery, David L. King, Yoshihiro Hisikawa and Wilhelm Warta, “Solar Cell Efficiency Tables (Version 27),” Res. Appl., Vol.14, pp.45–51, 2006
[24] Y. Bai, D. H. Ford, J. Rand and A. Barnett, Conf. Record of 26th IEEE Photovoltaic Specialists Conference, Anaheim, September/Octorber, pp.35-38, 1997.
[25] Yu Lei, Yu Jian-Zu and Wang Yong-Kun,“Measurement and analysis of thermal properties of SiN_x thin films,” Acta Physica Sinica, Vol 2, pp.77-81, 2004.
[26] A. Takami, S.Arimoto, H. Morikawa, S. Hamamoto, T. Ishihara, J. Kumabe, T. Murotani, In proc. 12th European Photovoltaic Solar Energy Conf., Stephens, UK, pp.59, 1994.
[27] Wen-Chang Yeh, Doctor Thesis of Tokyo Institute of Technology,“Study of excimer-Laser-Processed Polycrystalline-Silicon Thin-Film Solar Cell,” 2000.
[28] H. Kuriyama, S. Kiyama, S. Noguchi, T. Kuwahara, S. Ishida, T. Nohda, S.Ishida, K. Sano, H. Iwata, M. Osumi, S. Tsuda, S. Nakano and Y. Kuwano,” Enlargement of Poly-Si Film Grain Size by Excimer Laser Annealing and Its Application to High-Performance Poly-Si Thin Film Transistor” Jpn J. Appl. Phys., 30, pp.3700-3703, 1991.
[29] J. S. Im, H. J. Kim, and M. O. Thompson, ‘‘Phase Transformation Mechanisms Involved in Excimer Laser Crystallization of Amorphous Sillicon Films,’’ Appl. Phys. Lett., 63, 1969–71 (1993).
[30] D. H. Choi, K. Shimizu, O. Sugiura, and M. Matzumura, ‘‘Drastic Enlargement of Grain Size of Excimer-Laser-Crystallized Polysilicon Films,’’ Jpn. J. Appl. Phys., 31, 4545–9 (1992).
[31] K. Ishikawa, M. Ozawa, C. H. Oh, and M. Matsumura, ‘‘Excimer-Laser-Induced Lateral-Growth of Silicon Thin-Films,’’ Jpn. J. Appl. Phys., 37, 731–6 (1998).
[32] C. H. Oh, M. Ozawa, and M. Matsumura, ‘‘A Novel Phase-Modulated Excimer-Laser Crystallization Method of Silicon Thin Films,’’ Jpn. J. Appl. Phys., 37, L492–5 (1998).
[33] J. S. Im, R. S. Sposill and M. A. Crowder, “Single-crystal Si films for thin-film transistor devices” Appl. Phys. Lett., 70 (25), 3434, 1997.
[34] H. J. Kim and J. S. Im, “New excimer-laser-crystallization method for producing large-grained and grain boundary-location-controlled Si films for thin film transistors” Appl. Phys. Lett., 68 (11), 1513, 1996.
[35] A. Burtsev and R. Ishihara, ‘‘Enlargement of ‘‘Location Controlled’’ Si Grains by Dual-Beam Excimer-Laser With Bump Structures,’’ Appl. Surf. Sci., vol.154–5, (2000), pp.152-158.
[36] M. Hernandez, J. Venturini, D. Zahorski, J. Boulmer, D. Debarre, G. Kerrien, T. Sarnet, C. Laviron, M. N. Semeria, D. Camel, and J. L. Santailler, ‘‘Laser Thermal Processing for Ultra Shallow Junction Formation: Numerical Simulation and Comparison With Experiment,’’ Appl. Surf. Sci., Vol.208–209, pp.345–351(2003).
[37] K. Shimizu, S. Imai, O. Sugiura, and M. Matsumura, ‘‘Transient Temperature Profiles in Silicon Films During Pulsed Laser Annealing,’’ Jpn. J. Appl. Phys., 30, 2664–72 (1991).
[38] S. Chen and C. P. Grigoropoulos, ‘‘Noncontact Nanosecond-Time-Resolution Temperature Measurement in Excimer Laser Heating of Ni-P Disk Substrates,’’ Appl. Phys. Lett., 71, 3191–3 (1997).
[39] W. C. Yeh and M. Matsumura, ‘‘Numerical Calculation of Excimer-Laser-Induced Lateral-Crystallization of Silicon Thin-Films,’’ Jpn. J. Appl. Phys., 40, 492–9 (2001).
[40] C. H. Chang and L. S. Chao, ‘‘Modeling Analysis of Excimer Laser Crystallization of a-Si Films With Nanosecond Temperature Response,’’ Mate. Sci. Forum, 505–507, 283–8 (2006).
[41] H. Azuma, A. Takeuchi, T. Ito, H. Fukushima, T. Motohiro, and M. Yamaguchi, ‘‘Pulsed KrF Excimer Laser Annealing of Silicon Solar Cell,’’ Solar Energy Mater. Solar Cells, 74, 289–94 (2002).
[42] C. P. Grigoropoulos, S. Moon, M. Lee, M. Hatano, and K. Suzuki, ‘‘Thermal Transport in Melting and Recrystallization of Amorphous and Polycrystalline Si Thin Films,’’ Appl. Phys. A., 69, s295–8 (1999).
[43] M. Hatano, S. Moon, and M. Lee, ‘‘Excimer Laser-Induced Temperature Field in Melting and Resolidification of Silicon Thin Films,’’ J. Appl. Phys., 87, 36–43 (2000).
[44] Yu-Ru Chen, Chien-Hung Chang and Long-Sun Chao, 2007, “Modeling and Experimental Analysis in Excimer-laser Crystallization of Amorphous Si Films on Glass Substrate with Different Buffer Layers”, Journal of The American Ceramic Society, 90 [3], pp.688–692.
[45] W. Kurz and D. J. Fisher, Fundamentals of Solidification, 4th edition, Trans. Tech. Publications, Ltd, Switzerland, 1998.
[46] M. C. Flemings, Solidification Processing.McGraw-Hill Book Company, New York, USA, 1974.
[47] R.B. Bergmann, J. Kohler, R. Dassow, C. Zaczek and J.H. Werner: Phys. Stat. Sol. (a) Vol. 166 (1998), p. 587.
[48] J. S. Hsiao, “An Effective Algorithm for Finite Difference Analysis of Heat Transfer with Melting and Solidification,” Numerical Heat Transfer, Vol.8, pp.653-666, 1985.
[49] J. A. Dantzig: International Journal of Numerical Methods in Engineering Vol. 28 (1989), p. 1769.
[50] D. Bauerle, in: Laser Processing and Chemistry, Berlin, 1996, pp.581.
[51] Kallex Company: http://www.kallex.com.tw/up_compare.html
[52] Michael F. Modest, “Radiative Heat Transfer”, McGraw-Hill Book Company, 298-299 (1993).
[53] H. Kardestuncer and D. H. Norrie, “Finite Element Handbook”, Mcgraw-Hall book company, 1987
[54] Kenneth H. Huebner, Earl A. Thornton and Ted G. Byrom, “The Finite Element Method for Engineers”, Third edition, Wiley Interscience, 1995.
[55] E. D. Rainville, Elementary Differential Equations, 6th., Macmillan, New York, 1981.
[56] B. Carnahan, H. A. Luther, and J. O. Wilkes, Applied Numerical Method, Willy, New York, 1969.
[57] R.W. Lewis and K. Ravindran, Int. J. Numer. Methods Eng., 47, pp. 29-59, 2000.
[58] V. R. Voller and C. R. Swaminathan, Int. J. Numer. Methods Eng., 30, pp. 875-898, 1990.
[59] C. Bonacina and G. Comini, Int. J. Heat Mass Transfer, 16, pp. 1825-1832, 1973.
[60] M. Salcudean and Z. Abdullah, Int. J. Numer. Methods Eng., 25, pp. 445-473, 1988.
[61] Hu Heny and A. A. Stavros, Modeling Simul. Mater. Sci. Eng., 4, pp.371-396, 1996.
[62] Y. C. Liu and L. S. Chao, 2006, “Modified Effective Specific Heat Method of Solidification Problems,” Materials Transcation, Vol.47, No.11, pp. 2337-2744.
[63] C. H. Chang and L. S. Chao, 2008, “Modeling analysis of melting and solidifying processes in excimer laser crystallization of a-Si films with effective specific heat-enthalpy method”, International Communicatuons in Heat and Mass Transfer, V. 35, pp. 571-576,.
[64] Yu-Ru Chen, Chien-Hung Chang and Long-Sun Chao, 2007 “Modeling and Experimental Analysis in Excimer-laser Crystallization of a-Si Films”, Journal of Crystal Growth, 303, pp.199-202.
[65]R. Ishihara, A. Burtsev and Paul F. A. Alkemade, 2000, ‘‘Location-Control of Large Si Grains by Dual-Beam Excimer-Laser and Thick Oxide Portion,’’ Jpn. J. Appl. Phys. Vol.39, pp.3872-3878.

校內：立即公開
校外：2008-07-09公開

簡易檢索 / 詳目顯示

相關論文