藉由濕式蝕刻搭配蒸鍍技術增強電鍍銅背電極應用於單晶矽太陽能電池之特性研究

Improved Characteristics of Electroplating Copper as Rear Electrode of Monocrystalline Silicon Solar Cells by Wet Etching and Evaporation Process

周彥承(Yan-Cheng Jhou)

指導教授 ： 鄭錦隆

共同指導教授 ： 莊為群

國立虎尾科技大學/電機資訊學院/光電工程系光電與材料科技碩士班/碩士(2016年)

摘要

本研究藉由濕蝕刻搭配蒸鍍技術探討電鍍銅附著力進一步改善網印式單晶矽太陽能電池之光電特性，其中濕式蝕刻藥液包含硝酸銀或硝酸與氟酸之混合溶液，調配參數包含蝕刻濃度及時間，藉由電子掃描式顯微鏡探討兩種不同藥液濃度及蝕刻時間對表面的粗糙化效果及附著力效應，接著探討蒸鍍鎳當作電鍍晶種層效應，其中調變的參數包含電鍍鎳及蒸鍍鎳的厚度、後續的加熱溫度與時間及表面處理，達到最佳矽化鎳電阻率，最後使用電鍍銅技術來形成單晶矽太陽能電池背部電極。藉由拉力機測試附著力特性，同時調控鍍錫銅帶組成比及焊接溫度，比較電鍍銅背電極和傳統網印式太陽能電池背銀膠之間拉力的關係。
實驗結果顯示，當硝酸銀和氟酸濃度為0.03 M及1 M蝕刻時間為7分鐘得到奈米住長度約為450~550 nm之間，所殘留銀粒子由硝酸和去離子水1:1時間1分鐘去除，蒸鍍鎳為500 nm和電鍍鎳電流密度10 mA/cm2時間5分鐘總後度為800 nm，退火溫度400 ℃時間7分30秒，硫酸及雙氧水蝕刻溫度80 ℃時間2分鐘，電鍍銅電流密度25 mA/cm2時間30分鐘可獲得最佳實驗結果，結果顯示其單晶矽太陽能電池轉換效率為15.9%、開路電壓627 mV、短路電流密度31.5 mA/cm2及平均附著力為1.3 N/mm。

關鍵字

濕蝕刻 ； 電鍍銅 ； 附著力 ； 單晶矽太陽能電池 ； 光電特性

並列摘要

In this study, improved adhesion of electroplated copper as rear electrode of monocrystalline silicon solar cells (MSSCs) was presented by wet etching process. The wet etching solutions include silver nitrate (AgNO3)/hydrofluoric acid (HF) and nitrate (HNO3)/HF solution. The turned parameters include the solution concentration and the etching time. After wet etching, the surface morphologies were investigated by the scanning electron microscope (SEM). Furthermore, the effects of evaporated nickel film as seed layer was achieved. The parameters, including the evaporated and electroplating thickness, annealing temperature and time, as well as surface treatment, were addressed. Moreover, the rear copper electrode formed by electroplating was investigated. Finally, the adhesion characteristics were evaluated by peeling test. The parameters, including solder contents and solder temperature, were investigated. The adhesion characteristics, including electroplating copper and screen-printed rear silver paste, were compared.
The results show that the nanorods ranged from 450 to 550 nm were formed by the AgNO3/HF solution at 0.03/1 M and the etching time of 7 min. The residual silver can be removed by HNO3 and deionized water (DIW) solution at 1:1 and the etching time of 1 min. The nickel silicide seed layers can be formed by thermal evaporated and electroplating nickel of 800 nm and annealing at 400 ℃ for 7 min and 30 s. The surface treatment was achieved by the sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) with etching at 80 oC for 2 min. The current density and time of the electroplating copper were to be 25 mA/cm2 and 30 min, respectively. The results suggest that a conversion efficiency of 15.9% with an open voltage (Voc) of 627 mV, a short-current density (Jsc) of 31.5 mA/cm2, and peel force of 1.3 N/mm were demonstrated.

並列關鍵字

Wet etching ； electroplating copper ； adhesion ； monocrystalline silicon solar cells ； photovoltaic characteristics

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