本研究利用電漿輔助化學氣相沉積(Plasma enhanced chemical vapor deposition,PECVD) 製備異質接面太陽能電池表面鈍化超薄氫化非晶矽薄膜，利用 PECVD 具有穩定沉積速率、良好的覆蓋均勻性、低溫成長易與其他製程整合之特點。本實驗調變射頻功率、氫稀釋比例、基板溫度等製程參數探討對a-Si:H 薄膜鈍化特性影響。先以橢圓偏光儀來量測及分析薄膜的結構特性，再以少數載子生命週期來判斷薄膜鈍化品質好壞，以及有效提升電池開路電壓(Voc)並提升異質接面太陽能電池整體效率。
　　研究結果顯示，在50nm氫化非晶矽薄膜中，綜合所有製程參數並於少數載子生命週期(Lifetime)得知薄膜皆呈現良好鈍化品質，但是經過退火過程反而使內部Si-H鍵結成為亂序，造成鈍化品質下降。另一方面在超薄5nm氫化非晶矽薄膜中，藉由退火前後少數載子生命週期結果得知，薄膜結晶率對於表面產生的缺陷，可經由熱退火過程改善缺陷比例，增加在基板接面中的Si-H鍵將補償表面的懸掛鍵，降低薄膜中復合中心的產生進而提升少數載子生命週期，證明好的鈍化品質發生在非晶轉微晶的過渡區。我們可成功於H2/SiH4=4、射頻功率20W、基板溫140 ℃條件下得到5nm 超薄氫化非晶矽薄膜最佳鈍化效果，並在熱退火條件300 ℃-120sec時，少數載子生命週期可達到1.2 msec； implied Voc提升至0.694 V；並使表面復合速率下降至10 cm/s。且在4吋FZ-N矽晶基板上carrier lifetime到達4.7msec、Implied Voc值0.725V，表面復合速率下降至2.98 cm/s。將此優化非晶矽鈍化薄膜實際應用於異質接面矽晶(CZ-n)太陽能電池，在電池面積1cm2時，在電池開路電壓Voc=0.66 V; Jsc = 36.71 mA/cm2; F.F. = 71.75 %時，光電轉換效率達17.26%。

　　In this study, the intrinsic hydrogenated amorphous silicon (a-Si:H) thin films in heterojunction with intrinsic thin layer (HIT) solar cell was prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD). PECVD has several advantages, such as stable deposition rate, good coverage uniformity, low temperature growth and easy integration with other processes. The passivation quality of a-Si:H thin films was investigated by tuning the process parameters such as power, dilution ratio, and substrate temperature. Firstly, the thin film properties were measured and analyzed by Spectroscopic Ellipsometer. And the surface passivation quality of a-Si:H was determined by photo-conductance lifetime tester. Finally, a-Si:H films were applied to amorphous silicon / crystalline silicon heterojunction solar cells and improved the open-circuit voltage of solar cells.
　　The results show that the 50nm a-Si:H films can obtained high effective lifetime and good passivation quality for all process parameters with as-deposited condition, but after annealing treatment the passivation quality will decay because the Si-H bonds become disorder thus result in the reduction of effective lifetime. On the other hand, for the ultra-thin (5nm) a-Si:H films, after annealing treatment the effective lifetime increased. The high crystalline volume fraction will generated defects in the films or interface, after annealing process can improved the defects ratio, increase the Si-H bond at the substrate interface and compensate the surface dangling bonds, reduce recombination center and thus enhance the lifetime, that also prove the best passivation quality can be obtained with suitable amorphous to microcrystalline transition region. For ultra-thin (5nm) a-Si:H films, we obtained the high passivation quality under the condition of H2/SiH4=4, power of 20W, substrate temperature of 140℃, and after annealing process under the temperature 300 ˚C for 120 sec. The effective lifetime of a-Si:H film increased to 1.2 msec, the implied Voc increased to 0.694 V and cause the surface recombination velocity (SRV) decreased to 10 cm/s. In addition, the lifetime can reach 4.7 msec, implied Voc 0.725 V, the SRV drops to 2.98 cm / s on the 4-inch FZ-n silicon substrate. Moreover, the characteristics of HIT solar cell on CZ-n silicon substrate were shown as follow: Voc = 0.66 V, Jsc = 36.71 mA/cm2, F.F. = 71.75 %, efficiency = 17.26 % in the area of 1 cm2.

[1] J.J. Loferski,J.Appl.Phys.27,777 ,1956.
[2] 顧鴻濤，太陽能電池元件導論，全威圖書有限公司，台北，民國97 年。
[3] Swanson, R. M., “A vision for crystalline silicon photovoltaics”, Progress in Photovoltaics, Vol. 14, pp. 443-453, 2006.
[4] 黃惠良，曾百亨，太陽電池，五南出版社，民國97 年12 月。
[5] Hitoshi Sakata and Makoto Tanaka, “Sanyo’s Challenges to the Development of High-efficiency HIT Solar Cells and the Expansion of HIT Business”, IEEE 4th World Conference, 2006.
[6] Burrows, M. Z., et al., “Role of hydrogen bonding environment in a-Si:H films for c-Si surface passivation”, Journal of Vacuum Science & Technology A,Vol. 26(4), pp. 683-687, 2008.
[7] J. Sritharathikhun, C. Banerjee, M. Otsubo, T. Sugiura, H. Yamamoto, T. Sato, A. Limmanee, A. Yamada, M. Konagai, “Surface Passivation of Crystalline and Polycrystalline Silicon Using Hydrogenated Amorphous Silicon Oxide Film”, Japanese Journal of Applied Physics, Vol. 46(6A), pp. 3296-3300, 2007.
[8] M. Quirk and J. Serda, Semiconductor Manufacturing Technology, Ch.11 Deposition, 2001.
[9] 莊達人，VLSI 製造技術，高立圖書有限公司，1996.
[10] J. Venables, “Nucleation and Growth of Thin films”, Reports on Progress in Physics, Vol. 47, pp. 399-459, 1984.
[11] R.Schrop and M.Zeman, Amorphous and Microcrystalline Silicon Solar Cells: Modeling, Materials and Device Technology, Kluwer Academic, Boston, 1998.
[12] von Keudell and J. R. Abelson, “Direct insertion of SiH3 radicals into strained Si-Si surface bonds during plasma deposition of hydrogenated amorphous silicon films”, Physical Review B, Vol. 59, no. 8, Article ID 5791,1999.
[13] M. B. Howard, “Hydrogen collision model of light induced metastability in hydrogenated amorphous silicon”, Solid State Communications,Vol. 105, pp. 387-391, 1998.
[14] M. Stutzmann, W. B. Jackson and C. C. Tsai, “Light-induced metastable defects in hydrogenated amorphous silicon: A systematic study”, Physical Review B, Vol. 32, pp. 23, 1985.
[15] D. Redfield and R. H. Bube, “Defects in amorphous silicon Extrinsic or intrinsic”, Journal of Non-Crystalline Solids, Vol. 137 & 138, pp. 215-218, 1991.
[16] D. Staebler and C. Wronski, “Reversible conductivity changes in Discharge produced amorphous Si”, Applied Physics Letters, Vol. 31, pp. 292-294, 1977.
[17] A. Matsuda and K. Tanaka, Thin Solar Film 92,171, 1982.
[18] A. Matsuda, in Conference Record of the 25th IEEE photovoltaic Specialist Conference (IEEE, New York, 1996) p.1029, 1996.
[19] 陳治明，非晶半導體材料與器件，科學出版社，民國八十年。
[20] A. Matsuda, "Microcrystalline silicon. Growth and device application," Journal of Non-Crystalline Solids, Vol. 338, pp. 1-12, Jun 15 , 2004.
[21] D. L. Meier, M. R. Page, E. Iwaniczko, Y, Xu, Q. Wang, H. M. Branz, “Determination of Surface Recombination Velocities for Thermal Oxide and Amorphous Silicon on Float Zone Silicon”, 17th NREL Crystalline Silicon Workshop, August, 2007.
[22] 黃惠良，曾百亨，太陽電池，五南出版社，民國97 年12 月。
[23] T. S. Horanyi, T. Pavelka, P. Tutto, “In situ bulk lifetime measurement on silicon with a chemically passivated surface”, Applied Surface Science, Vol. 63, pp. 306-311, 1993.
[24] H. Fujiwara and M. Kondo, “Impact of epitaxial growth at the hetero interface of a-Si:H/c-Si solar cells”, Applied Physics Letters, Vol. 90, pp. 013503-013506, 2007.
[25] F. Zignani, A. Desalvo, E. Centurioni, D. Iencinella, R. Rizzoli, C.Summonte, A. Migliori et al., “Silicon heterojunction solar cells with p nanocrystalline thin emitter on monocrystalline substrate”, Thin Solid Films,Vol. 451–452, pp. 350–354, 2004.Vol. 451–452, pp. 350–354, 2004.
[26] M.H. Brodsky, Qiming Li, B.C Pan, and Y. Yoon, Phys.1 Rev. B, 57 , 2253 , 1998.
[27] U. Kroll, J. Meier,A. Shah, S. Mikhailov, and J, Weber, J. Appl. Phys. 80,4971 , 1996.
[28] Norbert H. Nickel: Hydrogen in semiconductor II, 61 , 1999.
[29] Min-sung Jeon* and Koichi Kamisako “Hydrogenated Amorphous Silicon Thin Films as Passivation Layers Deposited by Microwave Remote-PECVD for Heterojunction Solar Cells”, transactions on electrical and electronic materials vol. 10, no. 3, june 25, 2009.
[30] Minsung Jeon *, Shuhei Yoshiba, Koichi Kamisako “Hydrogenated amorphous silicon film as intrinsic passivation layer deposited at various temperatures using RF remote-PECVD technique”, Current Applied Physics 10 S237–S240 , 2010.
[31] Jia Ge, Zhi Peng Ling, Johnson Wong, Rolf Stangl, Armin G. Aberle, and Thomas Mueller, “Analysis of intrinsic hydrogenated amorphous silicon passivation layer growth for use in heterojunction silicon wafer solar cells by optical emission spectroscopy” , JOURNAL OF APPLIED PHYSICS 113, 234310 , 2013.
[32] Taguchi, M., et al., "24.7% Record Efficiency HIT Solar Cell on Thin Silicon Wafer." Ieee Journal of Photovoltaics 4(1): 96-99, 2014.
[33] 陳建勳, 非晶矽繞射光學元件的製作與分析, p10, 國立中央大學物理研究所碩士論文, 民國九十四年。
[34] P. Klement, C. Feser, B. Hanke, K. von Maydell, and C. Agert, "Correlation between optical emission spectroscopy of hydrogen/germane plasma and the Raman crystallinity factor of germanium layers," Appl. Phys. Lett., Vol. 102 (2013).
[35] Matsuda, M. Takai, T. Nishimoto, and M. Kondo, "Control of plasma chemistry for preparing highly stabilized amorphous silicon at high growth rate," Sol Energ Mat Sol C, Vol. 78, pp. 3-26 (2003).
[36] P. Tristant, Z. Ding, Q. B. Trang Vinh, H. Hidalgo, J. Jauberteau, J. Desmaison, and C. Dong et al., “Microwave Plasma Enhanced CVD of Aluminum Oxide Films：OES Diagnostics and Influence of the RF Bias”, Thin Solid Films, Vol. 390, pp. 51–58, 2001.
[37] 劉憲明，「寬能隙本質氫化非晶氧化矽(a-SiOx:H)薄膜光電特性與鈍化品質之關聯探討 」，機械工程學系光機電工程碩士班碩士論文，民國103 年。
[38] 樊洁平，劉惠民，田強，「光吸收介質的吸收係數與介電函數虛部的關係，大學物理，28 卷，3 期，民國98 年。
[39] 林明獻，太陽能電池技術入門，全華科技圖書股份有限公司印行 (2008) 。
[40] angelika gorgulla, nils brinkmann, anja bauer, giso hahn, barbara terheiden., “ influence of the electrodes distance upon the electrical, optical and structural properties of pecv-deposited hydrogenated amorphous silicon films for heterojunction solar cell application”, preprint to the 28th eu-pvsec, paris 2013.
[41] S. Lien, Y. Chang, Y. Cho, J. Wang and K. Weng et al., “Characterization of HF-PECVD a-Si:H thin film solar cells by using OES studies”, Journal of Non-Crystalline Solids, Vol. 357, pp.161–164, 2011.
[42] S. Ram, L. Kroely, S. Kasouit, P. Bulkin, and P.Roca et al., “Plasma emission diagnostics during fast deposition of microcrystalline silicon thin films in matrix distributed electron cyclotron resonance plasma CVD system”, physica status solidi© , Vol. 7, pp. 553–556, 2010.
[43] A.Szekeres, M.Gartner, F. Vasiliu, M. Marinov, G.Beshkov, “Crystallization of a-si:H films by rapid thermal annealing”, Journal of Non-Crystalline Solid, Vol. 227, pp. 954-957, 1998.
[44] A. Fontcuberta i Morral, P. Roca i Cabarrocas, and C. Clerc , “structure and hydrogen content of polymorphous silicon thin films studied by spectroscopic ellipsometry and nuclear measurements ”, physical review b 69, 125307, 2004.
[45] T. F. Schulze, H. N. Beushausen, C. Leendertz, A. Dobrich, B. Rech et al., “Interplay of amorphous silicon disorder and hydrogen content with interface defects in amorphous/crystalline silicon heterojunctions”, APPLIED PHYSICS LETTERS 96, 252102 , 2010.
[46] R. A. Street, Hydrogenated Amophous Silicon, Cambridge University Press, New York, 1991.
[47] Stefaan De Wolf and Michio Kondo., “Abruptness of a-Si:H/c-Si interface revealed by carrier lifetime Measurements ”, APPLIED PHYSICS LETTERS 90, 042111 , 2007.
[48] K. Kiriluk, J. Fields, B. Simonds, Y. Pai and P. Miller et al., “Highly efficient charge transfer in nanocrystalline Si:H solar cells”, Applied Physics Letters, Vol. 102, pp. 133101-133105, 2013.
[49] S. Kageyama, M. Akagawa and H. Fujiwara, “Dielectric function of a-Si:H based on local network structures”, Physical Review B, Vol. 83, Article ID 195205, 2011.