- 學位論文
利用AP-MOCVD成長氧化鋁薄膜對矽基板表面的鈍化效應研究
Silicon Surface Passivation Effect of Aluminum Oxide Films Grown by AP-MOCVD
摘要
本論文利用常壓式有機金屬氣相沉積法（AP-MOCVD）於p型Cz-Si上沉積氧化鋁薄膜，研究以氧化鋁薄膜作為p型Cz-Si表面鈍化層，使其能有效增加Cz-Si基板中少數載子生命週期。首先在有機金屬氣相沉積系統中以三甲基鋁（TMA）及不同流量的氧氣（O2）或水(H2O)作為沉積氧化鋁薄膜的來源，並通入氮氣（N2）作為乘載氣體在不同的沉積溫度沉積氧化鋁薄膜。再藉由快速熱退火爐（RTA）用forming gas(FGA)回火，再藉由微波反射光導衰減（μ-PCD）對基板的少數載子生命週期做量測並計算其表面複合速率(SRVs)並經由C-V量測探討表面固定電荷(Qf)跟少數載子生命週期的關係。實驗結果指出，在350℃的成長溫度下，通入三甲基鋁19umol/min與水35c.c/min，在用400℃的forming gas回火10分鐘，可以得到非常好的鈍化效果，少數載子生命週期從原先的185.337μs增加到1915.271μs表面複合速率為17.622cm/s。
並列摘要
Surface passivation of crystalline silicon (c-Si) is of key importance for the performance of high efficiency industrial solar cells. The surface to volume ratio is increasing due to the cost-driven reduction of the solar cell thickness, which makes surface passivation a decisive factor for the final solar cell efficiency.As the existence of Al/Si alloys formed by the sintering process with Aluminum glue in the backside of silicone solar cells, the defects on the surface of silicon substrate obviously increases, and the surface recombination velocity increases, too. In this study, aluminum oxide films grown on the CZ-silicon substrates by Atmospheric Pressure Metal-Organic Chemical Vapor Deposition (AP-MOCVD) technique. The AlOx films as the passivation layer on the CZ-Si substrate and the improvement of the minority carrier lifetime by the passivation effect is what we concerned. We use trimethyl aluminium (TMA), oxygen (or H2O) as the sources, nitrogen as carrier gas in AP-MOCVD system, and the growth of AlOx films in different flow rates of O2 (or H2O) and deposition temperatures.The AlOx films annealed by RTA system in the forming gas(FGA) environment, and the minority carrier lifetime we measured by microwave photoconductive decay (μ-PCD). The lowest surface recombination velocity we can get with TMA flow rate of 19umol/min, H2O flow rate of 35c.c/min and deposition temperature at 350℃ with 10 min annealing by forming gas at 400℃. The minority carrier lifetime increases from 185.337μs to 1915.271μs, and the surface recombination velocity we calculated up to 17.622cm/s.