本研究利用濕式氧化法，浸泡矽晶圓在68 %的硝酸溶液中製備氧化矽薄膜 (nitric acid oxidation of silicon)，搭配電子迴旋共振化學氣相沉積(electron cyclotron resonance chemical vapor deposition, ECRCVD)成長氮化矽薄膜堆疊於太陽能電池上，以達到表面鈍化的效果，探討其薄膜特性與其應用於元件上的表現。利用硝酸生成的氧化矽薄膜厚度在 1 ~ 2 nm 之間，與高溫成長的氧化矽相比，在很薄的情況下可以得到較高的緻密性和較低的漏電密度。 由於硝酸鈍化所形成的氧化層中，帶了少許的水氣與其他雜質，造成元件的不穩定與表面缺陷的產生。因此我們在硝酸形成氧化層之後，利用爐管通入不同的氣體修補表面的缺陷和去除水氣，經由電容-電壓量測和電流-電壓量測可得到氧化層的穩定度有進一步的提升。 本研究將針對在硝酸成長之氧化矽薄膜，在不同時間及熱處理下電容值的變化，分析氧化矽的性質。而後將氧化矽上堆疊氮化矽薄膜量測其載子生命週期，經由適當的熱處理可量測到載子生命週期達1700 us。最後將薄膜研究結果應用在單晶矽太陽能電池上，目前初步得到太陽能電池轉換效率(η) = 11.18 %；開路電壓(Voc) = 532 mV；短路電流(Jsc) = 36.72 mA/cm2；填充因子(FF) = 60.01 %。 In this study, we use wet oxidation to form silicon oxide films on silicon wafer in 68 % nitric acid. Electron cyclotron resonance chemical vapor deposition (ECRCVD) is used to growth silicon nitride films. We cap silicon nitride film on silicon oxide film, and to explore the film characteristics and the performance of monocrystalline silicon solar cells. The thicknesses of the silicon oxide layers grown under nitric acid is about 1~2 nm. Compare with the thermal growth of silicon oxide, the thin silicon oxide layers grown under nitric acid has high density quality and low leakage current. It has some surface defect in the thin silicon oxide layers grown under nitric acid. After preparing silicon oxide layers grown under nitric acid, we add different gas to the furnace for thermal anneal to remove surface defect. We can know the quality of silicon oxide layers by capacitance-voltage and current-voltage measurement. We investigate the change of capacitance in the silicon oxide layers grown under nitric acid with thermal annealing at different temperature. For the devices passivated by silicon oxide and silicon nitride, we can know that the lifetime elevates to 1700 us. Finally, we fabricate monocrystalline silicon solar cell with the optimized recipe of the passivation layer from the result that we investigated, and there we have the electro-optic convert efficiency = 11.18%, the open-circuit voltage (Voc) = 532 mV, short-circuit current density (Jsc) = 36.72 mA/cm2,and the fill factor (FF) = 60.01%.
