本論文是研究矽異質接面太陽能電池之製程和光電特性分析，我們使用離子佈植技術去形成太陽能電池的P型和N型重摻雜區，另外我們也對太陽能電池的抗反射層ITO ( Indium Tin Oxide ) 做製程條件上的優化。首先，我們在n-type單晶矽基板上用化學氣相沉積法同時沉積正反兩面 i-a-Si ( intrinsic amorphous silicon )，接著使用離子佈植技術去形成射極層( p+-a-Si )和背表面場( Back Surface Field, n+-a-Si )。而非晶矽有鈍化( passivate )單晶矽表面的作用，可以有效的修補太陽能電池的表面，進而提升太陽能電池的短路電流( Jsc )。本論文有四個主要的實驗。首先，我們找出ITO的最佳化製程參數，在直流濺鍍瓦數為110W時 ( rate=0.4A/s )，以及使用真空退火爐做400℃ 30分鐘的退火，讓我們的抗反射層ITO其厚度在80nm 時，擁有穿透率大於90% 以上、反射率小於15% 與片電阻為42 Ω/square 的電性與光學特性，以符合太陽能電池之抗反射層的需求。第二，我們將ITO製作在太陽能電池上，分別比較有無製程條件優化的ITO對太陽能電池特性之影響，由於被優化的ITO有很低的片電阻，我們發現ITO被優化的太陽能電池其Jsc 從34.44 mA/cm2 提升至35.44 mA/cm2，FF從0.629大幅提升至 0.694，效率也從11.71% 被提升到14.01%。第三，我們分別比較使用硼( B )和氟化硼( BF2 )當射極層( p+-a-Si )的離子佈植源，我們發現氟( F )可以降低a-Si的缺陷( defects )，且使用氟化硼當佈植源也可以達到較佳的淺接面( shallow junction )。從I-V curve我們發現使用氟化硼當佈植源的太陽能電池其Jsc 和Voc 有微幅的提升。第四，從SRIM模擬可以發現傾斜的離子佈植 ( tilt ion-implantation ) 可以達到比較好的淺接面( shallow junction )，從太陽能電池理論可以得知，較好的淺接面可以有比較好的Jsc 表現。因此我們以600傾斜的氟化硼離子佈植源去摻雜射極層( p+-a-Si )，從SIMS分析也可發現的確600傾斜的離子佈植可以達到較好的淺接面。我們分別去比較有無傾斜的離子佈植對太陽能電池效率的影響，我們發現以600傾斜的離子佈植太陽能電池其Jsc從35.44 mA/cm2 提升至36.85 mA/cm2，效率也從14.01% 提升到14.41%。在本論文中，我們將優化的ITO抗反射層製作在太陽能電池上，以氟化硼( BF2 )當射極層( p+-a-Si )的離子佈植源，並且以高角度600傾斜的離子佈植去形成射極層，以這樣的製程條件去製作太陽能電池將得到最佳化的效率。在元件面積為1cm2 和AM1.5的標準量測下，其Jsc = 36.85 mA/cm2 ，Voc = 0.565V，FF = 0.692，η=14.41% 為最佳化效率。

This thesis is studying the fabrication and analysis of a-Si/c-Si hetero-junction solar cell by using ion implantation technique, and the study of ITO ARC-layer ( anti-reflectance coating ) optimization. We use LPCVD to deposit i-a-Si on n-c-Si wafer, and use ion-implantation technique to form emitter-layer ( p+-a-Si ) and BSF ( back surface field, n+-a-Si ), this technique is quick than diffusion method. And a-Si has good passivation property at a-Si/c-Si interface, can reduce the dangling bonds at the interface, and increase the short-circuit current ( Jsc ) apparently. This thesis has four main experiments. First, we try to find the better process conditions of ITO by different sputter power and vacuum annealing. Afterwards, we analyze the electric property, optical property, and the crystallinity of ITO thin-film. By our investigation, we find the better process conditions of ITO is 110W sputter power and 400℃ 30min vacuum annealing, and the ITO has the best property for ARC-layer of solar cell. The sheet resistance is 42 Ω/square, transmittance is 91.57% and reflectance is 14.59% for the optimized ITO.
Second, we fabricate the optimized ITO ARC-layer on a-Si/c-Si solar cell, the Jsc is improved from 34.44 mA/cm2 to 35.44 mA/cm2 , FF is improved from 0.629 to 0.694 significantly, and the efficiency is improved from 11.71% to 14.01% due to the reduction of lateral resistance.
Third, we doping emitter layer of solar cell with BF2 or B source by ion implantation with ITO optimization. We find the efficiency of solar cell will be enhanced with BF2 source because Jsc and Voc is improved slightly due to the reduction of defects at a-Si and a-Si/c-Si interface by fluorine passivation. Forth, we can observe tilt ion implantation can achieve better shallow junction by SRIM simulation. From the theory of solar cell, we know shallower junction can get better Jsc and conversion efficiency will be enhanced. Hence, we dope emitter layer by 60o-tilt ion implantation with BF2 source. Afterwards, SIMS analysis can prove the tilt ion implantation can achieve better shallower junction certainly. By our investigation, we observe that Jsc is improved from 35.44 mA/cm2 to 36.85 mA/cm2 significantly, and the efficiency is improved from 14.01% to 14.41% by 60o-tilt ion implantation due to the better shallower junction.
In this thesis, we have achieved the better solar cell conversion efficiency of 14.41%, Jsc of 36.85 mA/cm2, Voc of 0.565V and FF of 0.692 ( AM1.5, area=1cm2 ) by ITO optimization and 600-tilt ion implantation with BF2 source.

[1] 王聪生 未来能源的发展 中國能源網 2010
[2] Yole Developpment , Market Share of solar cell , 2010
[3] Lawrence Kazmerski , NREL compilation of best research solar cell efficiencies , National Renewable Energy Laboratory (NREL), 2010
[4] Japan SANYO Electric Co. http://sanyo.com/news/2009/05/22-1.html
[5] K. Wakisaka, M. Taguchi, “ More than 16% solar cells with a new HIT structure” IEEE, Photovoltaic Specialists Conference, vol. 2, pp. 887 – 892, 1991
[6] Martin A. Green, “ Solar Cells Operating Principles, Technology and System Applications ”, The School of Photovoltaic and Renewable Energy Engineering, UNSW, 1982
[7] Yalan Hu, Xungang Diao, Cong Wng, Weichang Hao, Tianmin Wang , “ Effects of heat treatment on properties of ITO films prepared by RF magnetron sputtering ” Vacuum, vol. 75, pp. 183 – 188, 2004
[8] A.Madan, S.R. Ovshinesky, W. Czubatyj, M, Shur, “ Some Electrical and Optical Properties of a-Si:F:H Alloys ” Journal of Electronic Material, vol. 9, pp. 385 – 409, 1980
[9] S. M. Sze, “ Semiconductor Devices, physics and technology ”, 2nd Ed, 2002
[10] James D. Plummer, Michael D. Deal, Peter B. Griffin, “ Silicon VLSI
Technology: Fundamentals, Practice and Modeling ”, Prentice Hall, 2000
[11] Jenny Nelson, “ The physics of solar cells ” 2003
[12] Martin.A.Green, “ High-Efficiency Silicon Solar Cell ” , IEEE Transactions on Electron Device, vol. ED-31, NO. 5, 1984
[13] K.L. Chopraa, S. Majora and D.K. Pandyaa “ Transparent conductors—A status review ”, Thin Solid Films, vol. 102, pp. 1 – 46, 1983
[14] Wen-Fa Wu and Bi-Shiou Chiou “ Properties of radio-frequency magnetron
sputtered ITO films without in-situ substrate heating and post-deposition annealing ”, Thin Solid Films, vol. 247, pp. 201 – 207, 1994
[15] Jianhua Zhao, Aihua Wang, Martin A. Green “ 24.5% Efficiency silicon PERT
cells on MCZ substrates and 24.7% efficiency PERL cells on FZ substrates ” Progress in Photovoltaics: Research and Applications, Photovoltaics Special Research Centre, University of New South Wales, Sydney, NSW 2052, AUSTRALIE , vol. 7, pp. 471 – 474, 2000
[16] Mikio Taguchi, Akira Terakawa, Eiji Maruyama and Makoto Tanaka “ Obtaining a Higher Voc in HIT Cells ”, PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS, Prog. Photovolt: Res. Appl. 2005; 13:481–488
[17] Toru Sawada, Norihiro Terada, Sadaji Tsuge, Toshiaki Baba, T. Takahama, K. Wakisaka, S. Tsuda and S. Nakano, “ HIGH-EFFICIENCY a-Si/c-Si HETEROJUNCTION SOLAR CELL ”, IEEE Photovoltaic Specialists Conference, vol. 2, pp. 1219 – 1226, 1994
[18] Mikio Taguchi¬, Kunihiro Kawamoto, Sadaji Tsuge, Toshiaki Baba, Hitoshi Sakata, Masashi Morizane, Kenji Uchihashi, Noboru Nakamura, Seiichi Kiyama and Osamu Oota, “ HITTM Cells – High-Efficiency Crystalline Si Cells with Novel Structure ”, PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS, vol. 8, pp. 503 – 513, 2000
[19] M. Taguchi, H. Sakata, Y. Yoshimine, E. Maruyama, A. Terakawa and M. Tanaka, “ AN APPROACH FOR THE HIGHER EFFICIENCY IN THE HIT CELLS ”, Photovoltaic Specialists Conference, 2005
[20] Yasufumi Tsunomura, Yukihiro Yoshimine, Mikio Taguchi, Toshiaki Baba, Toshihiro Kinoshita, Hiroshi Kanno, Hitoshi Sakata, Eiji Maruyama, Makoto Tanaka, “ Twenty-two percent efficiency HIT solar cell ”, Solar Energy Materials & Solar Cells, vol. 93, pp. 670 – 673, 2009
[21] Takahiro Mishima, Mikio Taguchi, Hitoshi Sakata, Eiji Maruyama, “ Development status of high-efficiency HIT solar cells ”, Solar Energy Materials & Solar Cells, vol. 95, pp. 18 – 21, 2010
[22] Donghwan Kim, Younggun Han, Jun-Sik Cho, Seok-Keun Koh “ Low temperature deposition of ITO thin films by ion beam sputtering ”, Thin Solid Films, vol. 377 – 378, pp. 81 – 86, 2000
[23] Pung Keun Song, Yuzo Shigesato,1, Masayuki Kamei and Itaru Yasui, “ Electrical and Structural Properties of Tin-Doped Indium Oxide Films Deposited by DC Sputtering at Room Temperature ”, Japanese Journal Applied Physics, 38, pp. 2921 – 2927, 1999
[24] K.v. Maydell, L. Korte, A. Laades,R. Stangl, E. Conrad, F. Lange, M. Schmidt, “ Characterization and optimization of the interface quality in amorphous /
crystalline silicon heterojunction solar cells ”, Journal of Non-Crystalline Solids, vol. 352, pp. 1958 – 1961, 2006
[25] Horng Nan Chern, Chung Len Lee, Tan Fu Lei, “ The effects of fluorine passivation on polysilicon thin-film transistors ”, IEEE Transactions on Electron Device, vol. 41, pp. 698 – 702, 1994
[26] Yeon Sik Jung, Sung Soo Lee, “ Development of indium tin oxide film texture during DC magnetron sputtering deposition ”, Journal of Crystal Growth, vol. 259, pp. 343 – 351, 2003
[27] M. Schaper, J. Schmidt, H. Plagwitz and R. Brendel, “ 20.1%-efficient Crystalline Silicon Solar Cell with Amorphous Silicon Rear-surface Passivation ”, PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS, vol. 13, pp. 381 – 386, 2005
[28] W.S. Ho, Y-H. Huang, W.-W. Hsu, Y.-Y Chen, C.W. Liu, “ Ion Implanted Boron Emitter N-Silicon Solar Cells ”, SNDT, 2011
[29] J. C. C. Fan, F. J. Bachner, “ Properties of Sn-Doped In2O3 Films Prepared by RF Sputtering ”, J. Electrochemi, Soc. 122, pp. 1719 – 1724, 1975
[30] Y. Shigesato, Y. Hayashi, T. Haranoh, “ Electrical and structural properties of low resistivity tin‐doped indium oxide films ”, Appl. Phys. Lett., vol. 61, pp. 73 – 75, 1992