本論文主要是以陽極氧化方法來製做金氧半太陽能電池。傳統上，由於液相沉積法製做金氧半太陽能電池須耗時甚長但具有 10% 左右高轉換效率之優勢，而以陽極氧化方法來製做金氧半太陽能電池雖耗時短，但轉換效率卻不如液相沉積法。本文藉由電極設計改變以及製程改變以達成10%之高轉換效率以提升陽極氧化方法之競爭力。
在金氧半太陽能電池上鍍薄鋁可增加元件之抗反射能力並增加少數電子之收集能力，所以可提高元件之轉換效率，文中也探討出 6 奈米薄鋁厚度是一較佳之選擇；此外，薄鋁必須只覆蓋電極區域以防止與相鄰元件之並聯效應出現而造成量測結果過於樂觀。電極之設計須以在不使電極線電阻過大之前提下，盡量使曝光面積越大越好。藉由適當之電極設計以及鍍薄鋁可使轉換效率達到10% 以上。金氧半太陽能電池之轉換效率是否會隨時間改變也於文中探討；此外，量測時入射光源強度改變也被探討以評估量測結果是否客觀。
陽極氧化時，電解溶液之濃度亦會影響金氧半太陽能電池之轉換效率。不飽和電解溶液由於矽原子不足，必需由矽晶圓提供所以導至氧化層進入矽晶圓中；反觀飽和電解溶液法則完全將氧化層沉積於矽晶圓上，表現出較好之轉換效率。另外，改變陽極氧化之電流密度所造成之轉換效率改變亦於文中探討。

This thesis focus on discussing the conversion efficiency improvement of MOS solar cell prepared by Anodic Oxidation Process (ANO). By changing the pattern structure, MOS solar cell prepared by anodic oxidation in saturated H2SiF6 solution is demonstrated as a good way to in comparison with the performance of MOS solar cell prepared by LPD. The advantage of time saving as compared to LPD method has been achieved in this thesis.
The importance of thin Aluminum layer has been denoted in this thesis and 6nm is shown to be a good thin Al thickness for MOS solar cells. Besides, the coverage area of thin Aluminum film is suggested to be only on active area for lateral effect prevention. 10% conversion efficiency has been achieved by well-designed electrode pattern with thin Aluminum layer covered. Without the effect of the electrode serial resistance, the larger the exposure area will get the better performance of MOS solar cell. The aging test of MOS solar cell also was discussed in this thesis. It was found that the reduction of interface trap with time increasing will increase the conversion efficiency in a period of time and remain stable after that. This shows the MOS solar cells will not reduce the efficiency with time increase. By the changing of incident light power and the measurement of the performance of MOS solar cell, we get a conclusion that the results from 20 mW/cm2 incident power can be extended to 100 mW/cm2.
The ANO solution also was evaluated in this thesis, near saturation of H2SiF6 solution has been demonstrated to be the best for MOS solar cell fabrication in comparison with over saturation and under saturation of H2SiF6 solution. By measuring the saturation current under positive gate bias of MOS structure, it was found that the silicon oxide was formed in deposition when prepared by ANO with near saturation of H2SiF6 solution. Besides, from the changing of current density and preparation time in ANO process, the oxide thickness shows not be affected by current density change but the performance of MOS solar cell will be improved by increasing current density.

Contents
List of Tables ………………………………………………….….I
List of Figures …………………………………………………...II
Chapter 1 Introduction ………………………………………..1
1.1 Solar cell ………………………………………………………………………….1
1.2 I-V Characteristics ………………………………………………………………3
1.3 Anodic oxidation and pattern design ………………………………………. ….5
1.4 The measurement systems ………………………………………………………6
1.5 About this work ………………………………………………………………….6
Chapter 2 The Effect of Electrode Structure on MOS Solar Cell…7
2.1 Introduction ………………………………………………………………………7
2.2 Pattern design …………………………………………………………………….9
2.3 Experimental ……………………………………………………………………..9
2.4 Result and discussion …………………………………………………………. .11
2.4.1 Thin Al layer effect ………………………………………………………….11
2.4.2 The pattern effect ……………………………………………………………12
2.4.3 Time effect …………………………………………………………………..12
2.4.4 Post-metallization annealing (PMA) effect …………………………………13
2.4.5 Incident power effect ………………………………………………………..13
2.5 Summary …………………………………………………………………………14
Chapter 3 The Effect of ANO Process on MOS Solar Cell……15
3.1 Introduction ……………………………………………………………………..15
3.2 The H2SiF6 concentration effect ……………………………………………….16
3.2.1 The saturation current mechanism …………………………………………16
3.2.2 Experimental ……………………………………………………………….19
3.2.3 Results and discussion ……………………………………………………..20
3.3 The anodization current density effect ………………………………………...21
3.3.1 The experimental ……………………………………………………………21
3.3.2 Results and discussion ………………………………………………………22
3.4 Summary …………………………………………………………………………23
Chapter 4 Conclusion and Suggestion for Future work ……..24
4.1 Conclusion ………………………………………………………………………24
4.2 Suggestion for future work …………………………………………………….26
Tables
Figures
References

References
[1] M. A. Green, Jianhua Zhao, Aihua Wang, and Stuart R. Wenham, “ Very High Efficiency Silicon Solar Cell — Science and Technology”, IEEE Transactions on Electron Devices, Vol. 46, No. 10, October 1999.
[2] M. A. Green, Silicon Solar Cells: Advanced Principles and Practice. Sydney, Australia: Bridge Printery, 1995.
[3] M. Riordan and L. Hoddeson, Crystal Fire: The Birth of The Information Age. New York: Norton, 1997.
[4] J. Haynos, J. Allison, R. Arndt, and A. Meulenberg, “The comsat nonreflective silicon solar cell: A second generation improved cell” in Int. Conf. Photovolitac Power Generation, Hamburg, Germany, Sept. 1974, p487.
[5] R. B. Godfrey and M. A. Green, “655 mV open circuit voltage, 17.6% efficient silicon MIS solar cell”, Appl. Phys. Lett., vol. 34, pp.790-793, 1979.
[6] J. G. Fossum and E. L. Burgess, “High efficiency p+ n n+ back-surface-field silicon solar cell”, Appl. Phys. Lett., vol. 33, pp. 238-240, 1978.
[7] R. A. Sinton, Y. Kwark, P. Gruenbaum, and R. M. Swanson, “ Silicon point contact concentrator solar cell”, Cof. Record, 18th IEEE Photovoltaic Specialists Conf., Las Vegas, p. 61, 1985.
[8] A. W. Blackers, A. Wang, A. M. Miline, J. Zhao, and M. A. Green, “22.8% efficienct silicon solar cell”, Appl. Phys. Lett., vol. 55 p. 1363, 1989.
[9] A. Wang, J. Zhao, and M. A. Green, “24% efficiency silicon solar cells”, Appl. Phys. Lett., vol. 57, no. 6, p. 602, 1990.
[10] K. C. Lee and J. G. Hwu, “ 17.3% efficiency Metal-Oxide Semiconductor (MOS) sloar cells with liquid-phase-deposited silicon dioxide”, IEEE Electron Device Lett., vol 18, no. 11, pp. 565-567, 1997.
[11] M. Y. Doghish and F. D. Ho, “A comprehensive analytical model for Metal-Insulator-Semiconductor MIS devices: A solar cell application”, IEEE Transactions on Electron Device, vol. 40, pp. 1446-1454, 1993.
[12] 陳致豪, “ Application of anodization technique on MOS solar sell and ultra-thin gate oxide”, master degree thesis of EE department of NTU, 2001.
[13] E. H. Nicollian and J. R. Brews, “MOS Physics and Technology.” Wiley, New York, 1982.
[14] Mohamed Yehya Doghish and Fat Duen Ho, “A comprehensive Analytical Model for Metal-Insulator-Semiconductor Devices,” IEEE Trans. Electron Devices, vol. 39, no. 12, p.2771, 1992.
[15] 蘇建良, “Observation on the Thermal-Induced Stress Effect and Uniformity Improvement of Rapid Thermal Ultra-thin Gate Oxide”, master degree thesis of EE department of NTU, 2001.
[16] M. A. Green, “Resistivity dependence of silicon solar cell efficiency and its enhancement using a heavily doped back contact region”, IEEE Trans. Electron Devices, vol. ED-23, pp. 11-15, Jan. 1976.
[17] A. W. Blackers and M. A. Green, “20% efficiency silicon solar cell”, Appl. Phys. Lett., vol. 48, pp. 215-217, 1986.
[18] T. Saitoh, T. Uematsu, T. Kida, K. Matsukuma, and K. Morita, “Design and fabrication of 20% efficiency, medium-resistivity silicon solar cells”, in Conf. Rec. 19th IEEE Photovoltaic Specialists Conf., New Orleans, LA, 1987, pp. 1518-1519.
[19] W. T. Callaghan, “Crystalline silicon photovoltaic arrays: A final summaty of the flat-plate solar array project”, in 7th E. C. Photovoltaic Sol. Energy Con., Sivilla, Spain, Oct. 1986, pp. 792-799.
[20] R. A. Sinton, Y. Kwark, J. Y. Gan, and R. M. Swanson, “27.5% Si concentrator solar cells”, IEEE Electron Device Lett., vol. EDL-7, pp. 567, 1986.
[21] E. Yablonovitch, T. Gmitter, R. M. Swanson, and Y. H. Kwark, “A 720 mV open circuit voltage, SiOx double heterostructure solar cell”, Appl. Phys. Lett., vol. 47, pp. 1211-1213, 1985.
[22] R. R. King, R. A. Sinton, and R. M. Swanson, “Front and back surface fields for point-contact solar cells”, in Conf. Rec., 20th IEEE Photovoltaic Specialists Conf., Las Vegas, NV, Sept. 1988, pp. 538-544.
[23] M. A. Green, “Limits on the open-circuit voltage and efficiency of silicon solar cells imposed by intrinsic Auger processes”, IEEE Trans. Electron Devices, vol. ED-31, pp. 671-678, 1984.
[24] W. Shockley and H. J. Queisser, “Detailed balance limit of efficiency of p-n junction solar cells”, J. Appl. Phys., vol. 32, pp. 510-519, 1961.
[25] T. Tiedje, E. Yablonovitch, G. D. Cody, and B. G. Brooks, “Limiting efficiency of silicon solar cells”, IEEE Trans. Electron Devices, vol. ED-31, pp. 711-716, 1984.
[26] P. Cambell and M. A. Green, “The limiting efficiency of silicon solar cells under concentrated sunlight”, IEEE Trans. Electron Devices, vol. ED-33, pp. 234-239, 1986.
[27] A. Wang, J. Zhao, A. Aberle, S. R. Wenham, and M. A. Green, “717 mV open circuit voltage silicon solar cells”, Appl. Phys. Lett., vol. 64, pp. 199-201, 1994.
[28] M. A. Green, “ Limiting efficiency of bulk and thin-film silicon solar cells in the presence of surface recombination”, Progr, Photovolatics, to be published, 1999.
[29] S. Kolodinski, J. H. Werner, T. Wittchen, and H. J. Queisser, “Quantum efficiencies exceeding unity due to impact ionization in silicon solar cells”, Appl. Phys. Lett., vol. 63, pp. 2405-2407, 1993.
[30] P. Cambell and M. A. Green, “Light trapping properties of pyramidally textured surfaces”, J. Appl. Phys., vol. 62, pp. 243-249, 1987.
[31] A. G. Aberle, T. Lauinger, and R. Hezel, “Remote PECVD silicon─A key technology for the crystalline silicon PV industry of the 21st centry?”, in conf. Proc., 14th Europ. Photovotaic Sol. Energy Conf., Barcelon, Spain, 1997, pp. 684-689.
[32] T. Sawada, N. Terada, S. Tsuge, T. Bata, T. Takahama, S. Tsuda, and S. Naknano, “High efficiency a-Si/c-Si heterojunction solar cell”, in Conf. Rec., 1st World Conf. Photovoltaic Energy Conservation, 1994, pp. 1219-1225.
[33] Data sheet, BP Saturn Solar Cells, 1991.
[34] “ Alternative energy engineering: 1997-98 design guide and catalog”, Alternative Eng., Inc., Redway, CA, 1997.
[35] M. Camani, N. Cereghetti, D. Chianese, and S. Rezzonico, “Test of reliability on crystalline and amorphous silicon modules”, in Proc. 14th EC PV Sol. Energy Conf., Barcelona, Spain, June, 1997, p. 228.
[36] T. M. Bruton, G. Luthardt, K. D. Rasch, K. Roy, I. A. Dorrity, B. Garrard, L. Teale, J. Alonso, U. Ugalde, K. Declerq, J, Nijs, J. Szlufcik, A. Rauber, W. Wettling, and A. Vallera, “A study of the manufacture at 500 MWp p. a. of crystalline silicon photovoltaic modules”, in Conf. Rec. 14th Europ. Photovoltaic Sol. Energy Conf.”, Barcelona, Spain, June/July, 1997, pp. 11-16.
[37] D. H. Ford, J. A. Rand, A. M. Barnett, E. J. Delledonne, A. E. Ingram, and R. B. Hall, “Development of light-trapped, interconnected, silicon-film modules”, in Conf. Rec., 26th Photovoltaic Specialists Conf., Anaheim, CA, Sep./Oct., 1997, pp. 631-634.
[38] T. Bab, M. Shima, T. Matsuyama, S. Tsuge, K. Wakisaka, and S. Tsuda, “9.2% efficiency thin-film polycrystalline silicon solar cell by a novel solid phase crystallization method”, in Conf. Rec., 13th Europ. Photovoltaic Solar Energy Conf. Exhibit., Nice, France, Oct. 1995, p 1708.
[39] K. Yamamoto, T. Suzuki, M. Yoshimi, Y. Okamoto, Y. Tawada, and A. Nakajima, in 7th Workshop Role of Impurities and Defects in Silicon Device Processing, Vail, Aug., 1997, pp. 120-126.
[40] J. Meier, P. Torres, R. Platz, S. Dubail, U. Kroll, J. A. Anna Selvan, N. Pellaton Vaucher, C. Hot, D. Fischer, H. Keppner, A. Shah, and K. D. Ufert, ”Amorphous silicon technology”, in Mater. Res. Soc. Symp. Proc., vol. 420, pp. 3-14, 1996.
[41] M. A. Green and S. R. Wenham, “Novel parallel multijunction solar cell”, Appl. Phys. Lett., vol. 65, pp. 2907-2909, 1994.