半導體製程日益精進，其中離子佈植技術可活用植入的能量與劑量來形成高品質的淺接面太陽電池。一旦植入的能量設定越低，越多的摻雜原子則囤積於片子表面。在退火前使用濕式化學蝕刻可以輕易改變晶片表面的劑量。此調變表面劑量的方法可有效降低載子的複合速率。本研究利用這種劑量侷限的現象，使淺接面元件在單一個佈植參數的情況下做出多種摻雜濃度。試片分為全面及選擇性射極這兩種架構。這兩組射極結構各自分別進行兩種不同實驗流程，其程序為:1) 離子植入後的片子在退火前需經過濕式蝕刻； 2) 離子植入後的片子在退火後才進行濕式蝕刻。這兩種不同的蝕刻順序，在退火期間影響了片子內摻雜原子的密度。比較所有片子的少數載子壽命，發現退火前蝕刻的片子可提升至53.05 μs。其中選擇性射極的太陽電池具有明顯的藍移現象，進而提升元件之效率。

Ion implantation is an advanced technology developed to inject dopants for shallow junction formation. Due to the ion-induced sputtering effect at low implant energies where dopants tend to accumulate at the silicon surface, the excess ion doses can be easily removed via a surface chemical wet etching process. Modulating surface doses could enhance the collection of minority carriers through the substrate. By taking advantage of the dose limitation characteristic, this study proposed a novel method to form shallow emitters with various dopant densities. Each blanket and selective emitter structures with two process flows have been investigated: 1) Performing wet etch after implantation before junction anneal; 2) Performing wet etch after implantation and junction anneal. In the two process flows, we observed a difference in the density of doping impurities during the thermal process, which is related to the substrate recombination rates. Comparing the blanket emitter and selective emitter structures with two types of etching methods, the device with wet etch before annealing process achieved the best effective carrier lifetime of 53.05 μs, which led to a higher short circuit current density. Hence, this selective emitter cell demonstrated a better blue response and showed an improvement in the conversion efficiency.

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