本研究的目的在於探討經表面鈍化處理後之粗化n型矽晶圓之表面載子生命期。首先我們採用傳統的含IPA的鹼性蝕刻液與不含IPA的IPA-Free的鹼性蝕刻液兩種不同的蝕刻液對(100) n型矽基板進行表面的粗化製程，並比較蝕刻後矽基板表面對入射光的反射率，我們調整蝕刻液之溶液濃度、溫度、蝕刻時間及添加劑含量等製程參數，以改善蝕刻後矽金字塔結構之表面形貌及基板的反射率。
接著我們使用超臨界二氧化碳流體製程對晶圓做表面鈍化處理，並藉由添加雙氧水氧化矽晶圓表面，生成厚度約1 nm之氧化矽薄膜。我們以調整超臨界二氧化碳流體之壓力、反應時間及雙氧水的濃度來改善鈍化層氧化矽薄膜的鈍化品質，最後再使用VHF PECVD在晶圓表面成長厚度約30 nm的a-Si鈍化層，以氧化矽及a-Si雙層鈍化層修補矽晶圓表面因斷鍵所造成的缺陷。
在粗化製程部份，我們成功使粗化後的矽晶圓表面之加權平均反射率小於15%、金字塔的覆蓋率大於90%。在鈍化製程部份，我們測量鈍化後矽晶圓表面的載子生命期，僅有氧化矽鈍化層的矽晶圓表面在退火後之有效載子生命週期(@1015 cm-3)為6 µs，但由氧化矽及a-Si雙層鈍化層於退火後的有效載子生命週期達26.9µs。

The purpose of this study is to investigate the surface carrier lifetime of a texturized n-type (100) Si wafer after surface passivation. The surface texturization on the Si wafer using isopropanol-free alkaline solution was performed and compared with that of using conventional isopropanol alkaline etchant. Texturization conditions, such as concentration of etchant, etching temperature, and etching time were optimized to reduce optical reflection of the Si surface.
The surface passivation of the Si surface was first formed by growing a 1 nm thick SiOx used the supercritical carbon dioxide (SCCO2) fluid with H2O2 additive. We varied the operation pressure and time of the SCCO2, together with H2O2 concentration to optimize the performance of the SiOx passivation layer. After growing the SiOx thin film, we deposited a 30 nm thick a-Si by VHF PECVD to further improve the defects cause by the silicon dangling bond on the Si surface.
The weighted reflectivity and surface coverage of pyramid of the textured Si substrates of better than 15% and 90% were achieved. On the other hand, lifetime of the carriers was measured by a home-made photoconductance system. The effective carrier lifetime (@1015 cm-3) of texturized silicon substrate with SiOx surface passivation was 6 µs. The carrier lifetime was further increased to 26.9 µs when SiOx and a-Si double-layered passivation was used.

第一章 導論 1
1-1 太陽能電池簡介 1
1-2 影響效率之因素 2
1-3 文獻回顧 3
1-3-1 矽基板表面之粗糙化製程添加物 3
1-3-1-1 異丙醇(Isopropyl alcohol, IPA) 3
1-3-1-2 異丙醇取代物(IPA-Free) 3
1-3-2 矽基板表面鈍化 3
1-3-2-1 非晶矽薄膜 4
1-3-2-2 二氧化矽薄膜 4
第二章 實驗方法 5
2-1 實驗設備 5
2-1-1 氫氧化鉀蝕刻製程 5
2-1-2 超臨界系統 5
2-1-3 濺鍍系統(Sputtering) 6
2-1-4 超高頻電漿輔助化學氣相沉積(VHF PECVD) 7
2-1-5 量測設備 8
2-1-5-1 場發射型掃描式電子顯微鏡（FE-SEM） 8
2-1-5-2 紫外光-可見光光譜量測儀 9
2-1-5-3 橢圓偏振量測儀 9
2-1-5-4 載子生命週期量測儀 10
2-2 實驗流程 11
2-2-1 清洗基板 11
2-2-2 溼蝕刻 12
2-2-3 RCA清潔 12
2-2-4 表面鈍化 12
第三章 不同蝕刻參數之表面結構與反射率結果分析 13
3-1 KOH/IPA 13
3-2 KOH/IPA-Free 18
第四章 不同蝕刻參數之表面載子生命週期結果分析 21
4-1 KOH/IPA 22
4-2 KOH/IPA-Free 23
4-3 表面鈍化 25
第五章 結論 29
參考文獻 30

[1] "Best Research-Cell Efficiencies, National Renewable Energy Laboratory (NREL)", 2017.
[2] M. Tanaka, M. Taguchi, T. Matsuyama, T. Sawada, S. Tsuda, S. Nakano, H. Hanafusa, and Y. Kuwano, "Development of new a-Si/c-Si heterojunction solar cells: ACJ-HIT (artificially constructed junction-heterojunction with intrinsic thin-layer)," Japanese Journal of Applied Physics, vol. 31, no. 11R, pp. 3518, 1992.
[3] K. Yoshikawa, H. Kawasaki, W. Yoshida, T. Irie, K. Konishi, K. Nakano, T. Uto, D. Adachi, M. Kanematsu, and H. Uzu, "Silicon heterojunction solar cell with interdigitated back contacts for a photoconversion efficiency over 26%," Nature Energy, vol. 2, pp. 17032, 2017.
[4] P. Papet, O. Nichiporuk, A. Kaminski, Y. Rozier, J. Kraiem, J.-F. Lelievre, A. Chaumartin, A. Fave, and M. Lemiti, "Pyramidal texturing of silicon solar cell with TMAH chemical anisotropic etching," Solar Energy Materials and Solar Cells, vol. 90, no. 15, pp. 2319-2328, 2006.
[5] B. Stegemann, J. Kegel, O. Gref, U. Stürzebecher, A. Laades, K. Wolke, C. Gottschalk, and H. Angermann, "Conditioning of textured silicon solar cell substrates by wet-chemical treatments," in Proc. 27th European Photovoltaic Solar Energy Conference, pp. 547-551, 2012.
[6] S. Rattanapan, T. Watahiki, S. Miyajima, and M. Konagai, "Improvement of rear surface passivation quality in p-type silicon heterojunction solar cells using boron-doped microcrystalline silicon oxide," Japanese Journal of Applied Physics, vol. 50, no. 8R, pp. 082301, 2011.
[7] S.-Y. Lien, Y.-S. Cho, Y. Shao, C.-H. Hsu, C.-C. Tsou, W. Yan, P. Han, and D.-S. Wuu, "Influence of surface morphology on the effective lifetime and performance of silicon heterojunction solar cell," International Journal of Photoenergy, vol. 2015, 2015.
[8] D. Muñoz, P. Carreras, J. Escarré, D. Ibarz, S. M. De Nicolás, C. Voz, J. Asensi, and J. Bertomeu, "Optimization of KOH etching process to obtain textured substrates suitable for heterojunction solar cells fabricated by HWCVD," Thin Solid Films, vol. 517, no. 12, pp. 3578-3580, 2009.
[9] J. Krümberg, I. Melnyk, M. Schmidt, M. Michel, T. Fidler, M. Kagerer, P. Fath, L. Heiliger, and H. Nussbaumer, "New innovative alkaline texturing process for CZ silicon wafers," in 24th European Photovoltaic Solar Energy Conference, pp. 1748-1750, 2009.
[10] J. Kegel, H. Angermann, U. Stürzebecher, and B. Stegemann, "IPA-free texturization of n-Type Si wafers: Correlation of optical, electronic and morphological surface properties," Energy Procedia, vol. 38, pp. 833-842, 2013.
[11] Z. C. Holman, A. Descoeudres, L. Barraud, F. Z. Fernandez, J. P. Seif, S. De Wolf, and C. Ballif, "Current losses at the front of silicon heterojunction solar cells," IEEE Journal of Photovoltaics, vol. 2, no. 1, pp. 7-15, 2012.
[12] P. Cuony, M. Marending, D. Alexander, M. Boccard, G. Bugnon, M. Despeisse, and C. Ballif, "Mixed-phase p-type silicon oxide containing silicon nanocrystals and its role in thin-film silicon solar cells," Applied Physics Letters, vol. 97, no. 21, p. 213502, 2010.
[13] J. B. Heng, J. Fu, B. Kong, Y. Chae, W. Wang, Z. Xie, A. Reddy, K. Lam, C. Beitel, and C. Liao, "> 23% high-efficiency tunnel oxide junction bifacial solar cell with electroplated Cu gridlines," IEEE Journal of Photovoltaics, vol. 5, no. 1, pp. 82-86, 2015.
[14] T. Oikawa, K. Ohdaira, K. Higashimine, and H. Matsumura, "Application of crystalline silicon surface oxidation to silicon heterojunction solar cells," Current Applied Physics, vol. 15, no. 10, pp. 1168-1172, 2015.
[15]https://zh.wikipedia.org/wiki/超臨界流體.
[16] A. Perret, P. Chabert, J. Jolly, and J.-P. Booth, "Ion energy uniformity in high-frequency capacitive discharges," Applied Physics Letters, vol. 86, no. 2, pp. 021501, 2005.
[17] A. M. B. van Mol, "Chemical vapour deposition of tin oxide thin films," 2003.
[18] S. Palchoudhury, M. Baalousha, and J. Lead, "Methods for measuring concentration (mass, surface area and number) of nanoparticles," Characterization of Nanomaterials in Complex Environmental and Biological Media, eds Baalousha M, Lead J (Elsevier, Amsterdam), pp. 153-177, 2016.
[19] W. Favre, L. Bettaieb, J. Després, J. Alvarez, J.-P. Kleider, Y. Le Bihan, Z. Djebbour, and D. Mencaraglia, "Coil-to-sample distance influence on contactless QSSPC effective lifetime measurements: application to silicon wafers passivated by thin amorphous layers," in 26th EU PVSEC, pp. 1563-1568, 2011.
[20] P. Drummond, D. Bhatia, A. Kshirsagar, S. Ramani, and J. Ruzyllo, "Studies of photoconductance decay method for characterization of near-surface electrical properties of semiconductors," Thin Solid Films, vol. 519, no. 22, pp. 7621-7626, 2011.
[21] 賴世偉, "利用氧化亞銅與 N 型矽基板製作太陽能電池," 中山大學光電工程研究所學位論文, pp. 1-62, 2016.