太陽能電池可分成三代電池，分別是矽晶、薄膜與新觀念太陽能電池，因為矽本身產量豐富，而且矽晶電池製程技術與半導體製程相近，現今太陽能電池市場主要以矽晶電池為主，約佔市場九成。目前市場矽晶高效產品以P型背面鈍化型結構電池(Passivated Emitter and Rear Cell, PERC)為主，透過背面鈍化、高效率射極等結構後，效率已可超過22.5 %以上。在高效矽晶電池研究中，減少載子復合是非常重要的技術，自2006年來，以氧化鋁(Al2O3)為主的鈍化層已普遍應用在p型與n型矽晶太陽能電池中，PERC電池所使用鈍化材料與技術上，目前常用材料為氧化鋁，因為氧化鋁層擁有較強的負電荷，可以在P型矽基材提供較佳的電荷斥回效應，利用場效應降低介面電子電洞複合，進而降低電池內載子壽命的損失，此外，此層氧化物材料也須能提供較佳之化學鈍化特性，藉由矽材與鈍化層介面的保護，來減少對於介面缺陷的產生。二氧化鈦這材料尚未應用在量產電池中，但本身因為能帶結構與折射率可作為載子選擇層與抗反射膜而受到關注。
原子層沉積系統(Atomic layer Deposition, ALD)技術可以沉積覆蓋性佳且均勻的薄膜，有別於一般傳統化學氣相沉積的成長方式，前驅物依序地被引進反應腔體裡面，藉由前驅物在基材表面的飽和化學吸附及自我限制的化學反應，將原子一層一層地堆疊起來，使得每一次進氣循環的過程，僅形成厚度為一層原子的薄膜，此項特性讓控制鍍膜厚度的精確性可達原子級(約0.1nm)的精度而且階梯覆蓋性佳，以現有鍍膜技術評估，原子層沉積系統所鍍製的薄膜層較為緻密，且具有較低之缺陷電荷，因此利用ALD進行鈍化膜層的製備，較適用來進行不同鈍化層材料的探討。
沉積後的退火過程，溫度、時間深深影響鈍化層的表現，例如溫度影響會改變鈍化層晶相、矽與氧化層之間介面鍵結等等，本研究利用原子層沉積系統分別沉積不同厚度之氧化鋁與二氧化鈦在矽基板雙面，嘗試改變退火溫度得到優化的鈍化層，使用少數載子壽命測試儀測量樣品的少數載子壽命(Lifetime, Ⴀ)、飽和電流(saturation current density, J0)與隱開路電壓(implied open-circuit voltage, iVoc)，利用準穩態光電導模式(Quasi-Steady-State photoconductance, QSSPC)分析鈍化效果，由穿透式電子顯微鏡觀察膜層厚度、介面特徵，配合X光能譜分析儀探討退火對於氧化鋁與二氧化態之鈍化影響，評估其鈍化表現對於矽晶電池的應用方向。

Al2O3 has been widely used in silicon solar cells as the passivation material. Thinner wafers can improve efficiency while reducing costs. However, thinner wafers require lower process temperatures resulting in surface defects account for a higher proportion of overall defects. Therefore, the deposition technology of the passivation layer becomes more important.

The Atomic Layer Deposition (ALD) is an unique technology for depositing a thin film with good coverage and uniformity. The deposited film is dense and has a very low defect charge. In this research, using ALD to develop Al2O3 and SiO2 composite film passivation layer and the emerging material TiO2 film explores its passivation characteristics by manipulating the annealing temperature. It is found that the passivation effect of the Al2O3 composite film is significant with the annealing temperature of 400°C, and decreases at 600°C. The additional SiO2 in the interface helps to induce more negative charges. In addition, with the development of new materials, the TiO2 film layer has the best passivation performance without heat accumulation causing by annealing.

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