本實驗將開發旋轉塗佈摻雜(spin-on dopant, SOD)擴散製程，並應用於製作N型PERT雙面太陽能電池，藉由兩次擴散驅動溶質(硼、磷)進入矽晶格形成電池射極 (Emitter) 與背表面電場 (Back surface field, BSF)，相較於傳統的氣體擴散源(BBr3或POCl3)製程，SOD製程技術具有成本低、製程速度快等優點；此外也不具有毒性可提高生產線運作的安全性。
首先我們對溶劑成分進行調配，初始先在小尺寸基板上開發出能均勻析出之溶劑，接著配合塗佈時轉速配置使其在5x5 cm2面積上也可達到均勻化，並探討擴散製程參數如氣氛、時間、濃度與溫度達其最佳化，製作出具低電阻率Emitter與BSF層並有效降低其少數載子複合。
最終我們結合所探討的條件條件，將其結果應用於太陽能電池元件上，得到太陽能電池轉換效率(η) = 12.8 %；開路電壓 (Voc ) =579.99 mV；短路電流 (Jsc) = 34.53 mA/cm2；填充因子 (FF) = 63,9 %。

In this experiment, we have developed a spin-on dopant (SOD) diffusion technique for fabrication of n-type passivated emitter and rear cell (PERC) solar cells. Compared with traditional diffusion of gases dopant (BBr3 or POCl3), SOD technique could lower the manufacturing cost and improve production efficiency. Furthermore, it is not toxic which can raise safety on production line.
We first adjusted component ratio of dopant source, which can be spreaded on a small-sized substrate uniformly. Then we explore the rotation speed of spin coating to achieve uniformity of sheet resistance on 5x5 cm2 and investigate the parameters of diffusion such as atmosphere, time, concentration and temperature to get low sheet-resistance and high lifetime.
Finally, we fabricated monocrystalline N-type silicon solar cell base on optimized conditions and the electro-optical convertion efficiency = 12.8 % ; the open-circuit voltage (Voc) = 579.99 mV, short-circuit current density (Jsc) = 34.53 mA/cm2 and the fill factor (FF) = 63.9 %.

[1] Data from Global Market Outlook for Photovoltaics 2014-2018 and Global Market Outlook for Solar Power 2015-2019
[2] D. M. Chapin, C. S. Fuller, G. L. Pearson, Journal of Applied Physics, 25, 676, (1954).
[3] Data from GTM Research PV Pulse
[4] Data from International Technology Roadmap for Photovoltaic (ITRPV) & http://www.itrpv.net/
[5] A. Wang, J. Zhao, M.A. Green, Applied physics letters, 57, 605 (1990).
[6] J. Schmidt, K. Bothe, R. Bock, C. Schmiga, R. Krain, R. Brendel, 22nd European Photovoltaic Solar Energy Conference, 3-7 September (2007).
[7] M. wolf, H. Rauschenbach, Advanced energy conversion, 3, 455-479 ,1963
[8] S.O. Kasap “Optoelectronics and Photonics Principles and Practices, Prentice –Hall”, 2001.
[9] H. Hoppe, N. S. Sariciftci, “Organic solar cells”, Journal of materials research, 19, 1924-1945 ,2004.
[10] B. Fischer, “Loss analysis of crystalline silicon solar cells using photo-conductance and quantum efficiency measurements”, PhD Thesis, University of Konstanz , 2003.
[11] R. Schimpe, “Theory of reflection at the facet of a semiconductor-laser”, International Journal of Electronics and Communications, 46, 80-85 ,1992.
[12] H. Park et al, International Journal of Photoenergy, 794867 (2012).
[13] G. Singh, V. Amit, R. Jeyakumar, The Royal Society of Chemistry, 4, 4225–4229 (2014).
[14] A. Das, PhD dissertation, Atlanta, Georgia, Georgia: Institute of Technology, School of Electrical and Computer Engineering (2012).
[15] J. Peter , IEEE Transactions on electron devices, 53, 3 (2006).
[16] H. Park et al, International Journal of Photoenergy, 794867 (2012).
[17] K.S. Ryu, PhD dissertation ,Georgia Institute of Technology (2015).
[18] V. D. Mihailetchi, Proc. 25th Eur. Photovoltaic Sci. Eng. Conf., 1446–1448 (2010).
[19] G. Singh, The Royal Society of Chemistry, 4, 4225–4229 (2014).
[20] J. LIBAL. et al., Proceedings of the 22th European Photovoltaic Solar Energy Conference, 1382-1386 (2007).
[21] J. Y. Lee and S. W. Glunz, Proc. 19th EU-PVSEC, 998-1001 (2004).
[22] G. Bueno, Proc., 20th EU-PVSEC, 1458-1461 (2005).
[23] A. Das, PhD dissertation, Atlanta, Georgia, Georgia: Institute of Technology, School of Electrical and Computer Engineering (2012).
[24] B. Terheiden, Energy Procedia, 92, 486, (2016)
[25] D. S. Kim, M. M. Hilali, A. Rohatgi, K. Nakano, A. Hariharan, K. Matthei, Journal of The Electrochemical Society, 153, A1391, (2006)
[26] K. Ryu, A. Upadhyaya, V. Upadhyaya, A. Rohatgi and Y. W. Ok, Prog. Photovolt: Res. Appl., 23, 119, (2015)
[27] T. S. B¨oscke, D. Kania, C. Sch¨ollhorn, D. Stichtenoth, A. Helbig, P. Sadler, M. Braun, M. Dupke, M. Wei, A. Grohe, J. Lossen, and H. J. Krokoszinski, IEEE JOURNAL OF PHOTOVOLTAICS, 4, 48, (2014)
[28] Diborane Material Safety Data Sheet, Praxair, Rev. Date May 2009.
[29] Silane Material Safety Data Sheet, Praxair, Rev. Date 10/15/2007.
[30] S. W. Tan, W. T. Chen, M. Y. Chu and W. S. Lour, “Sub-0.5-µm gate doped-channel field-effect transistors with HEMT-like channel using thermally reflowed photoresist and spin-on glass”, science and technology, 2003.
[31] Y. Ishihara*, T. Hirai, C. Sakurai, T. Koyanagi, H. Nishida, M. Komatsu “Applications of the particle ordering technique for conductive antireflection films”, Thin Solid Films, 2002.
[32] Zhoukun He, Meng Ma, Xiaorong Lan, Feng Chen,* Ke Wang, Hua Deng, Qin Zhang and Qiang Fu, “Fabrication of a transparent superamphiphobic coating with improved stability”, Soft Matter, 2011
[33] Zih-Wei Peng, Masahiro Nakahara, Thomas Buck, and Radovan Kopecek “Towards 22% efficiency n-PERT rear junction solar cells with screen printed Al point back contact”, AIP Conference Proceedings 1999, 100002 , 2018
[34] Kyung Sun Ryu, “DEVELOPMENT OF LOW-COST AND HIGH-EFFICIENCY COMMERCIAL SIZE N-TYPE SILICON SOLAR CELLS”, 2016.
[35] Vanessa da Conceição Osório, Adriano Moehlecke and Izete Zanesco,” Influence of the order of boron and phosphorus diffusion on the fabrication of thin bifacial silicon solar cells” IOP Science, 2016.
[36] B. Bazer-Bachi etal., “Higher emitter quality by reducing inactive phosphorus”, Solar Energy Materials & Solar Cells, 2017.
[37] Ajeet Rohatgi, Brian Rounsaville, Young-Woo Ok, Andrew M. Tam, Francesco Zimbardi, Ajay D. Upadhyaya, Yuguo Tao, Keeya Madani, Armin Richter, Jan Benick, and Martin Hermle “Fabrication and Modeling of High-Efficiency Front Junction N-Type Silicon Solar Cells With Tunnel Oxide Passivating Back Contact”, IEEE JOURNAL OF PHOTOVOLTAICS, 2018.
[38]Ning Yang ,Shizheng Li ,Jinlin Yang ,Hongbo Li ,Xiaojun Ye ,Cui Liu ,Xiao Yuan, “Avoidance of boron rich layer formation in the industrial boron spin-on dopant diffused n-type silicon solar cell without additional oxidation process”, Journal of Materials Science: Materials in Electronics, 2018.
[39] Toshio Joge et al, “Low-Temperature Boron Gettering for Improve the Carrier Lifetime in Fe-Contaminated Bifacial Silicon Cells with n+pp+ Back-Surface-Field Structure”, Jpn. J. Appl. Phys., 42, 5397-5404 (2003).
[40] YichaoWu et al, “Suppression of boron-oxygen defects in Czochralski silicon by carbon co-doping”, Applied Physics Letters, 106, 102105 (2015).
[41] N. Ganagona, L. Vines, E. V. Monakhov, and B. G. Svensson, “Transformation of divacancies to divacancy-oxygen pairs in p-type Czochralski-silicon mechanism of divacancy diffusion”, J. Appl. Phys., 115, 034514 (2014).
[42] Chao Gao, Yunhao Lu, Peng Dong, Jun Yi, Xiangyang Ma, and Deren Yang, “Boron deactivation in heavily boron-doped Czochralski silicon during rapid thermal anneal: Atomic level understanding”, Applied Physics Letters, 104, 032102 (2014).
[43] Fa-Jun Ma et al, “Two-dimensional numerical simulation of boron diffusion for pyramidally textured silicon”, J. Appl. Phys., 116, 184103 (2014).
[44] C. Gao, Y. Lu, P. Dong, J. Yi, X. Ma, and D. Yang, “Boron deactivation in heavily boron-doped Czochralski silicon during rapid thermal anneal: Atomic level understanding”, Applied Physics Letters, 104, 032102 ,2014.
[45] F. Ma et al, “Two-dimensional numerical simulation of boron diffusion for pyramidally textured silicon”, J. Appl. Phys., 116, 184103 ,2014.
[46] M.Oriowsk,”Unified model for impurity diffusion in silicon”Appl.Phys.Lett, 53(14),1988.
[47] B. Bazer-Bachi etal., “Higher emitter quality by reducing inactive phosphorus”, Solar Energy Materials & Solar Cells, 105, 137-141 (2012).
[48] V. D. Mihailetchi, Proc. 25th Eur. Photovoltaic Sci. Eng. Conf., 1446–1448 (2010).