本實驗將開發結合旋轉塗佈摻雜(spin-on dopant, SOD)技術之局部雷射摻雜(laser doping, LD)擴散製程。此製程技術可用於製作選擇性射極(selective emitter, SE)結構於矽晶太陽能電池；亦具潛力應用於其他半導體元件之局部高摻雜層製作。相較於傳統的氣體摻雜源，SOD 製程技術具有成本低、安全性高等優點；另一方面相較於以離子佈植與短波長雷射系統製作SE的方式，本研究重點為開發二氧化碳(CO2)雷射進行局部高摻雜結構製作，除了可有效減少設備成本並能降低製程中之表面缺陷產生。研究初期透過自行撰寫之模擬程式計算雷射製程參數對矽晶圓表面溫度變化之影響並藉此優化後續製程參數。透過SOD結合局部雷射摻雜製作之SE結構，淺摻雜與重摻雜區之片電阻可根據需求分別控制在100-150 Ω/sq 與50-80 Ω/sq。 在太陽能電池實作成果方面，本研究所開發之SOD擴散製程結合CO2雷射摻雜製作具SE結構之N型PERT(鈍化射極及背面全擴散)雙面太陽能電池，其相較於均勻性emitter結構之電池，光電轉換效率可提升0.26%，開路電壓提升4.31 mV，短路電流提升0.92 mA/cm2。;In this experiment, a local laser-doping technique based on a spin-on-dopant source and carbon dioxide (CO2) laser has been developed with the purpose of implementing selective emitter (SE) structures in bifacial n-type PERT (passivated emitter rear totally diffused) silicon solar cells. Compared with the conventional gas diffusion sources, our SOD process has the advantages of low cost and non-toxicity. Regarding the SE processing, compared to ion implantation and short-wavelength laser systems, we used carbon dioxide (CO2) laser system to perform the fabrication of SE structures on Si wafers, which can effectively reduce both of the equipment costs and surface defects generated during the process. After optimization of the process parameters, the sheet resistance of the lightly-doped and heavily-doped zone could be controlled at 100-150 Ω/sq and 50-80 Ω/sq on demand, separately. Finally, SE N-PERT (passivated emitter rear totally diffused) Si solar cells were fabricated using the CO2 laser doping combined with SOD diffusion process. Compare to the reference cell with a homogeneous emitter structure, the selective emitter solar cell improves the efficiency 0.26%, the open circuit voltage 4.31 mV, the short circuit current 0.92 mA/cm2.
