本研究於自製電漿輔助化學氣象沉積系統利用光放射光譜端點檢測以進行異質接面太陽能電池用氫化非晶矽鈍化薄膜之適用製程研究。透過電漿診斷及硬體回饋以即時提供電漿變化趨勢，大幅減少不必要之製程測試實驗，而縮短製程開發成本。 首先根據本研究薄膜分析結果顯示，在固定製程氣體總流量為70sccm下，量測鈍化矽晶片所得載子lifetime隨功率提高有明顯下降趨勢（由900µs~200µs），而其薄膜微結構因子（R*~0.3）卻無明顯之變化趨勢。但在製程電漿時序光譜發現電漿解離瞬間（暫態）之SiH*強度較穩定狀態（穩態）時高，表示該瞬間之前趨物SiHX濃度較高使得薄膜沉積速度較快；同時暫態電子溫度指標（Hβ/Hα）也高於穩態，代表此時電漿具有較強離子轟擊，而造成矽晶與鈍化薄膜介面產生缺陷使得矽晶鈍化成效下降。而上述之暫態與穩態差異性隨功率上升而增加，且在調變製程氣體總流量為30sccm時也呈現一樣之變化趨勢。因此判定電漿暫態與穩態差異性越大，其薄膜介面受損越嚴重，造成鈍化效果下降。 由此電漿光放射光譜端點檢測研究成果驗證獲得矽晶表面鈍化明顯受電漿解離瞬間之狀態影響，也提供一電漿製程開發及適用區間的技術及準則。 ;In this study, the process of hydrogenated amorphous silicon (a-Si:H) thin films for application in heterojunction with intrinsic layer (HIT) solar cell is prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD). The characterization of plasma process is studied by using Optical emission spectrometer (OES). The passivation quality of a-Si:H thin films was determined by photo-conductance lifetime tester and the microstructure factor of the films was determined by Fourier-Transform Infrared Spectrometer (FTIR). The results show that the surface passivation is affected by the state of plasma. According to stability of SiH*, the plasma reaction can be defined as stable state and transient state. The value of SiH* is much higher in the transient state than in the stable state. It means that the SiHX concentration are much higher when the plasma state is in transient state. On the other hand, the ratio of Hβ/Hα can be defined as an electronic temperature (Te). In the transient-state plasma, the electronic temperature is higher and it indicates the ion bombardment get stronger. With the stronger ion bombardment, the damage between the silicon wafer and the passivation layer is greater. Therefore, the change of plasma state can be used to diagnose and monitor the plasma processing condition and use it to receive an immediate process feedback afterwards. We can cut down the unnecessary process step time and reduce the cost of the research.
