- 學位論文
藉由快速熱退火製程增強網印式單晶矽太陽能電池光電特性之研究
Improved Photovoltaic Characteristics of Screen-Printed Mono-Crystalline Silicon Solar Cells by Rapid Thermal Annealing Process
摘要
本研究藉由快速熱退火(RTA)製程增強網印式單晶矽太陽能電池之光電特性，首先調變雷射損傷後的蝕刻濕製程及快速熱退火的樣品擺放樣式、氣體種類、製程溫度及時間、蒸鍍鎳厚度與矽化鎳後的濕蝕刻製程製作高品質的電鍍銅晶種層，最後搭配電鍍銅當作網印式單晶矽太陽能電池的背電極，其中雷射損傷後的蝕刻濕製程為改變KOH的蝕刻液體量，¬而快速熱退火的樣品擺放樣式包括P-type裸片墊底蒸鍍面朝下、P-type裸片墊底蒸鍍面朝下再用P-type裸片覆蓋住、蒸鍍面朝上與蒸鍍面朝上用P-type裸片覆蓋住，氣體種類包含N2及成形氣體(5%H2混合95%N2)，快速熱退火溫度從325 oC變化至425 oC，其製程時間為3至7分鐘，至於矽化鎳後的濕蝕刻製程則採用改變H2SO4/H2O2混合液體的蝕刻時間，最後搭配改變電鍍銅的電鍍時間來製作高品質的網印式單晶矽太陽能電池之電鍍銅背電極。 實驗結果顯示，當雷射損傷後增加KOH蝕刻的液體量有助於提升太陽能電池的光電轉換效率從15.2%至15.8%，擺放方式中以P-type裸片墊底蒸鍍面朝下再用P-type裸片覆蓋住為最佳方式，可讓元件光電轉換效率從14.1%至15.3%，而通入氣體中氮氣與成型氣體效率皆達到15.3%，考量氣體價格，本實驗以氮氣為後續研究的製程氣體，當快速熱退火溫度從325變化至425 oC搭配製程時間從3變化至7分鐘時，較佳參數為350 oC，製程時間為5分鐘時，可讓元件光電轉換效率從13.9%提升至15.8%。
並列摘要
In this thesis, improved photovoltaic characteristics of screen-printed mono-crystalline silicon solar cells (SPMSSCs) were investigated by the rapid thermal annealing (RTA) process. First, the wet solution process for laser damage removal was demonstrated. Then, the effects of the placed way of the samples, the gas ambient, the temperature, time, the thickness of the nickel, and the wet etching of residual nickel on the quality of the seed layer for electroplated copper were presented. Finally, the copper was electroplated as the rear electrode of the SPMSSCs. The amount of the KOH solution for laser damage removal was achieved. Four placed ways, including the evaporated surface faced to top of the p-type substrate, the evaporated surface faced to top of the p-type substrate was covered by the p-type substrate, the evaporated surface up, as well as the p-type substrate faced to top of the evaporated surface, were addressed. The nitrogen and forming gas (5%H2+95%N2) were used as the process gas. The temperature of the RTA ranged from 325 to 425 oC was achieved. The time of the RTA ranged from 3 to 7 min was explored. The etching time of the SPM solution for residual metal removal was investigated. The results indicate that the increase of the KOH solution amount was help to enhance the conversion efficiency (CE) of the SPMSSCs from 15.2 to 15.8%. Compared with all placed ways, “the evaporated surface faced to top of the p-type substrate was covered by the p-type substrate” was the best condition for CE improvement. The CEs of the SPMSSCs were identical for the nitrogen and forming gas. Thus, the cheap nitrogen gas was used for CE improvement. The achievement of an CE improvement of more than 1.9% absolute from 13.9% to 15.8% in SPMSSCs with the RTA at 350 oC for 5 min was explored.