背面鈍化堆疊層在PERC太陽能電池中扮演很重要的一個角色。Al2O3為一種同時兼具場效鈍化及化學鈍化的優異材料。本實驗將以氧化鋁作為鈍化層，並以氮化矽作為鈍化保護層覆蓋在鈍化層上方，兩種薄膜沉積後都會分別經過不同參數的退火，來找出使少數載子生命週期提升最大的參數。
本實驗使用電子束蒸鍍系統沉積一層鋁於背面，以臭氧氧化的方式將鋁氧化成氧化鋁。我們分別對蒸鍍厚度、氧化時間、退火溫度及退火時間做測試，找出蒸鍍3nm鋁、氧化20分鐘、700度退火60秒為最佳。藉由XPS量測可以得到Al2O3薄膜的元素組成，並以TEM量測知道Al2O3薄膜的厚度，再以C-V量測得到退火後鈍化層的負電荷密度。接著沉積氮化矽作為鈍化保護層後進行不同退火溫度及時間的二次退火，發現最佳退火溫度及時間為400度20分鐘，還能防止鈍化層衰退。最後以所有最佳參數製成之PERC太陽能電池達到最佳填充因子為76 %、轉換效率為17.093 %，比背部全面鋁的太陽能電池相比提升了0.329 %。

The rear side passivation stack layer plays an important role in PERC solar cells. Al2O3 is an excellent material with the features of both field-effect passivation and chemical passivation. In this experiment, aluminum oxide was first used as the passivation layer, and silicon nitride layer was used as the protection layer that covers the passivation layer. The two layers were annealed with different post deposition annealing conditions to find out the parameters that maximize the minority carrier lifetime.
In this experiment, an electron beam evaporation system was used to deposit a layer of aluminum on the back, and the aluminum was oxidized into aluminum oxide by ozone oxidation. We measured the minority carrier lifetime by varying deposition thickness, oxidation time, annealing temperature, and annealing time, and found that the best minority carrier lifetime occurred with the deposition of 3nm aluminum, 20 minutes of oxidation, and 60 seconds of annealing at 700 ℃. The elemental composition of the Al2O3 film was measured by XPS, and the thickness of the Al2O3 film was measured by TEM, and then the negative charge density of the passivation layer after annealing was measured by C-V measurement. Next, silicon nitride was deposited as a protection layer, and then were subjected to second annealing with different annealing temperatures and times. It was found that the optimal annealing temperature and time were 400 ℃ for 20 minutes, which can also prevent the passivation layer from degrading. Finally, the PERC solar cell made with all the best parameters achieves an optimal fill factor of 76 % and a conversion efficiency of 17.093 %, which is 0.329 % higher than that of Al-BSF.

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