太陽能電池之研究近年來快速發展，而在致力於提升效率的同時，如何降低整體製程之成本也是一門重要的課題。本篇論文利用化學濕式蝕刻的方式對單晶太陽能電池進行表面的蝕刻，在表面形成倒金字塔之結構，有助於進一步降低表面反射率，增加入射光進入電池內產生載子的機會。另外我們也以臭氧氧化金屬鋁的方式，取代傳統ALD製程，使用較低成本的方法在晶片背面形成氧化鋁的鈍化層，透過這一層氧化鋁層可以在背面形成負電荷層，將對晶片產生場效鈍化之效果，如此一來便能夠提升長波長之入射光在背表面之吸收，降低背表面復合速率以及提升少數載子生命週期。

本論文使用臭氧氧化金屬鋁形成背面氧化鋁鈍化層，透過不同之氧化鋁層製程參數，如鍍鋁厚度、氧化時間、退火溫度、退火時間，探討少數載子生命週期的提升效果，而論文中為了證實氧化鋁層具有鈍化效果，使用XPS、TEM、C-V量測以及IQE量測分別進行探討，最後，我們得出之最佳製程參數為，鍍鋁厚度3nm，氧化時間20分鐘，退火溫度600°C進行退火90秒，由此參數製程之倒金字塔PERC太陽能電池的最佳轉換效率可以達16.92%，比起無PERC結構之倒金字塔太陽能電池參考片提升0.6%絕對值之效率。

Research on solar cells has been developed rapidly in recent years. While working to improve efficiency, how to reduce the cost of the manufacturing process is also an important issue.
We use a chemical wet etching method to texture the surfaces of monocrystalline solar cells, forming an inverted pyramid structure on the surfaces, which helps to reduce the surface reflectivity and increase light incidence into cell to generate carriers. In addition, we use ozone gas to oxidize aluminum instead of an ALD process, to obtain a cost-effective method to form the passivation layer of aluminum oxide on the back side of the wafer. With this passivation layer, negative charges can be produced at the Si/Al2O3 interface, which contribute a field-effect passivation. Therefore, the absorption of long-wavelength incident light can be increased, and the recombination rate can be reduced, leading to an increase in the minority carrier lifetime.

We use ozone gas to oxidize aluminum to form the aluminum oxide passivation layer on the back side.Various passivation layer process parameters, such as aluminum thickness, oxidation time, annealing temperature, and annealing time period for improving the lifetime of minority carrier are discussed. In order to verify the passivation effect of the aluminum oxide layer, XPS, TEM, CV measurement and IQE measurement were used. Finally, we obtained the best process parameters as follows: aluminum thickness 3nm, oxidation time 20 minutes, annealing temperature 600 °C for 90 seconds. The best conversion efficiency of the inverted pyramid PERC solar cell can reach 16.92%, which is 0.6% higher than the inverted pyramid solar cell without a PERC structure.

[1] Lyon, “Recreating Edmond Becquerel’s Electrochemical Actinometer”,Archives Des Sciences, Arch Sci, pp.147-156,2005
[2] American Physical Society, “Bell Labs Demonstrates the First Practical Silicon Solar Cell” ,from
https://www.aps.org/publications/apsnews/200904/physicshistory.cfm
[3] National Renewable Energy Laboratory (NREL), “Best Research-Cell Efficiency Chart” ,from
https://www.nrel.gov/pv/cell-efficiency.html
[4] 國家能源科技培訓計畫, “太陽能電池元件材料及其元件種類”,from
https://sites.google.com/site/ensatptd/tai-yang-guang-dian-fa-dian
[5] 聯合再生能源,“Black21 Series Ultra-Efficient” ,from
https://www.urecorp.com/Product_solarpower_battery.php#fixed
[6] Energy Conversion Devices, “Development in Understanding and Controlling the Staebler-Wronski Effect in a-Si:H ”, Vol:31, pp.47-49, 2001
[7] A.Blakers, ” Development of the PERC Solar Cell”, IEEE Journal of Photovoltaics ,Vol:9 ,pp. 629-635 ,2019
[8] Y. Zhiqin, L. Mingdun, Y. Xi, H. Can, L. Jingqi, L. Junshuai, L. Yali, G. Pingqi, and Y. Jichun,” High-Performance Black Multicrystalline Silicon Solar Cells by a Highly Simplified Metal-Catalyzed Chemical Etching Method”, IEEE Journal of Photovoltaics, pp.888-893, 2016
[9]中興物理 孫允武,“半導體概論”,from
http://ezphysics.nchu.edu.tw/prophys/condmatt/handouts/chap8semicon/semicond.pdf
[10] 維基百科,“p3混成軌域”,from https://zh.wikipedia.org/wiki/Sp3%E6%9D%82%E5%8C%96
[11] M. L. Cohen, & T. K. Bergstresser, “Band Structures and Pseudopotential Form Factors for Fourteen Semiconductors of the Diamond and Zinc-blende Structures”, Physical Review, 141(2), pp.789-796,1966
[12] P. Hervé and L.K.J. Vandamme,“General Relation Between Refractive Index and Energy Gap in Semiconductors”, Infrared Physics & Technology ,Vol:35, pp. 609-615,1994
[13] S.M. SEZ, & M.K. LEE ”Semiconductor Devices Physics and Technology(3rd Edition)”, JOHN WILEY & SONS, INC, pp.20
[14] Chemistry LibreTexts,“Miller index,”from
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Book%3A_Surface_Science_(Nix)/01%3A_Structure_of_Solid_Surfaces/1.02%3A_Miller_Indices_(hkl)
[15] S.M. SEZ, & M.K. LEE ”Semiconductor Devices Physics and Technology(3rd Edition)”, JOHN WILEY & SONS, INC, pp.22
[16] P. Swan, “ The Relation between Zero-Energy Scattering Phase-Shifts, the Pauli Exclusion Principle and the Number of Composite Bound States”, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 228(1172), pp.10-33,1955.
[17] W. Shockley, “ Energy Band Structures in Semiconductors”, Physical Review,78(2), pp. 173-174,1950
[18] D. K. Schroder, “The Concept of Generation and Recombination Lifetimes in Semiconductors”, IEEE Transactions on Electron Devices, 29(8), pp. 1336-1338,1982
[19] S.M. SEZ, & M.K. LEE ”Semiconductor Devices Physics and Technology(3rd Edition)”, JOHN WILEY & SONS, INC, pp.28
[20] W. Schockely,H. J. Queisser, “Detailed Balance Limit of Efficiency of p-n Junction Solor Cells”, Journal of Applied Physics,32(3),pp. 510-519,1961
[21] F. Houqiang & Z. Yuji,” Efficiency droop in GaInN/GaN LEDs”, Nitride Semiconductor Light-Emitting Diodes (LEDs) (Second Edition), 2018
[22] S.M. SEZ, & M.K. LEE ”Semiconductor Devices Physics and Technology(3rd Edition)”, JOHN WILEY & SONS, INC, pp.23
[23] S.M. SEZ, & M.K. LEE ”Semiconductor Devices Physics and Technology(3rd Edition)”, JOHN WILEY & SONS, INC, pp.34
[24] R. C. Willson, & A. V. Mordvinov, “Secular Total Solar Irradiance Trend During Solar Cycles” , Geophysical Research Letters, 30(5),pp. 21-23,2003
[25] H. D. Liu, C .H. Lin, K. J. Pai, Y. L. Lin,” A Novel Photovoltaic System Control Strategies for Improving Hill Climbing Algorithm Efficiencies in Consideration of Radian and Load Effect”, Energy Conversion and Management,Vol:165,pp.815-826,2018
[26] National Renewable Energy Laboratory (NREL),” Reference Air Mass 1.5 Spectra”,from
https://www.nrel.gov/grid/solar-resource/spectra-am1.5.html
[27]臺大電機系科普系列, “淺談太陽能電池的原理與應用”,from
https://ee.ntu.edu.tw/upload/hischool/doc/2014.04.pdf
[28] W. J. Yang,Z. Q. Ma,X. Tang,C. B. Feng,W. G. Zhao, & P. P. Shi,“ Internal Quantum Efficiency for Solar Cells”, Solar Energy, 82(2),pp. 106-110,2008
[29] W. P. Mulligan, D. H. Rose, M. J. Cudzinovic, D. M. De Ceuster, K. R. McIntosh,
D. D. Smith and R. M. Swanson, “Manufacture of Solar Cells with 21% Efficiency”, proceedings 19th European Photovotaic Solar Engery Conference, 2004
[30] G. Agostinelli, A. Delabie, P. Vitanov, Z. Alexieva, H. F. W. Dekkers, S. De Wolf and G. Beaucarne, “Very Low Surface Recombination Vlocities on p type Silicon Wafers Passivated with a Dielectric with Fixed Negative Charge”, Solar Energy Materials & Solar Cells, pp. 3438-3443, 2006
[31] I. Martin, M. Vetter, A. Orpella, J. Puigdollers, A. Cuevas and R. Alcubilla, “Surface Passivation of p-type Crystalline Si by Plasma Enhanced Chemical Vapor Deposited Amorphous SiCx: H Films”, Appl. Phys. Lett., pp. 2199-2201, 2001
[32] O.V. Roos, “A Simple Theory of Back Surface Field (BSF) Solar Cells”, Journal of Applied Physics, pp. 3503-3511, 1978
[33] A. Kaminski, B. Vandella, A. Fave, J.P. Boyeaux, L. Q. Nam, R. Monna, D. Sarti and A. Laugier, "Aluminum BSF in Silicon Solar Cells", Solar Energy Material & Solar Cells, pp. 373-379, 2002
[34] S. Gajendra, A. Verma, and R. Jeyakumar, "Fabrication of c-Si Solar Cells Using Boric Acid as a Spin-on Dopant for Back Surface Field", RSC, Adv. 4.9, pp. 4225-4229. 2013
[35] S.M. SEZ, & M.K. LEE ”Semiconductor Devices Physics and Technology(3rd Edition)”, JOHN WILEY & SONS, INC, pp.162
[36] J. M. Delarios, C. R. Helms, D. B. Kao, & B. E. Deal,” Effect of Silicon Surface Cleaning Procedures on Oxidation Kinetics and Surface Chemistry”, Applied Surface Science, 30(1-4), pp. 17–24,1987
[37] K. A. Salman, “ Effect of Surface Texturing Processes on the Performance of Crystalline Silicon Solar Cell”, Solar Energy, 147, pp. 228-231,2017
[38] H. Haibing, L. Jun, B. Yameng, X. Rongwei, S. Shenghua, S. Sami, L. Shuo, M. Chiara, S. Hele, W. Aihua, Z. Jianhua,” 20.8% Industrial PERC Solar Cell: ALD Al2O3 Rear Surface Passivation, Efficiency Loss Mechanisms Analysis and Roadmap to 24%. “Solar Energy Materials and Solar Cells, 161, pp.14-30,2017
[39] M. Jonghun, P. Srikanta, S. Rajkumar, C. Jaeho, K. Keunjoo,” Thermal Annealing Effect on the Conversion Efficiency of Si Solar Cells”,Journal of Nanoelectronics and Optoelectronics, Vol:13, Number 10, pp. 1557-1563,2018
[40] Z. Suxiang, Q. Qi, Z. Song, J. Jingjia, S. Zhengrong, L. Guohua.” Rear Passivation of Commercial Multi-Crystalline PERC Solar Cell by PECVD Al2O3”, Journal of Applied Surface Science, pp. 66-70,2014
[41] J. W. Lin , Y. Y. Chen , J. Y. Gan , W. P. Hseih , C. H. Du , T. S. Chao,” Improved Rear-Side Passivation by Atomic Layer Deposition Al2O3/SiNx Stack Layers for High VOC Industrial p-Type Silicon Solar Cells” Journal of IEEE Electron Device Letters ,Vol:34 ,Issue: 9 ,pp. 1163-1165,2013
[42]蕭宏,”半導體製程技術導論第三版” ,全華出版社 ,pp. 180-204
[43] J. Chen, Z. H. J. Tey, Z. R. Du, F. Lin, B. Hoex & A. G. Aberle, “ Investigation of Screen-Printed Rear Contacts for Aluminum Local Back Surface Field Silicon Wafer Solar Cells“,IEEE Journal of Photovoltaics, pp. 690-696,2013
[44] C. J. Son, T. Y. Kim, T. G. Park & S. W. Lim, “ Is Highly Selective Si3N4/SiO2 Etching Feasible without Phosphoric Acid”, Solid State Phenomena, pp. 147-151,2018