表面鈍化技術於高效率太陽能電池製程上為不可或缺的一環。近年來研究指出，氧化鋁於矽基太陽能電池之P型側鈍化上表現亮眼，歸功於氧化鋁與矽基板介面上具備負電荷性質造成之場效鈍化，可阻退少數載子接近材料表面，降低載子於表面受懸浮鍵再結合之機率，此外氧化鋁之化學鈍化性質亦不容小覷，因此該材料具備極大的潛力於鈍化製程上。
本研究致力於以非真空水溶液系統沉積高品質氧化鋁鈍化薄膜，取代現今廣為使用之真空鍍膜系統，已達到製程簡化、設備便宜等需求。實驗結果指出沉積溫度30℃下，磁石轉速500rpm沉積1小時後並以去離子水清洗，具備較佳之基板表面鈍化性質。熱退火製程上，氮氣環境以550℃退火處理40分鍾，除了幫助沉積之氧化鋁薄膜有效鍵結鈍化懸浮鍵，也能活化氧化鋁負電荷累積。
另外採用產業界經常使用的鈍化氣體氫氣，作為退火氣氛之摻雜氣體，藉以填補未被鍵結之懸浮鍵，觀察鈍化效果提升程度。最後期許將以上製程最佳參數穩定應用到大面積之基板，得到液相沉積氧化鋁鈍化薄膜製程，具有幫助太陽能電池提升效率之結果。

The alumina thin films were coated by low cost liquid phase deposition (LPD) and it indeed can reduce the surface recombination velocity which was measured by lifetime tester Sinton WCT-120 in the quasi-steady state mode. In order to compete with the passivation performance of conventional such expensive methods, PECVD and ALD, the best quality of oxide thin films need to be obtained by LPD method. In this study, aluminum sulfate with crystallized water and sodium bicarbonate were used as the precursors, and deposition conditions such as pH value, stirrer rotation speed, and deposition time must be optimized. Furthermore, substrate pretreatment will improve thin films quality, due to the solution can easier to contact with a hydrophilic surface, and this property will enhance the films more continuous and dense. We used either plasma or nitric acid treatment to modify the substrate surface becomes hydrophilic. In addition, the post-deposition processes are necessary. DI water washing process will retain the films quality and annealing process will enhance both chemical and field-effect passivation performance. Our goal is reduce SRV value less than 100 cm/s and using those techniques in large-size wafer fabrication process.

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