本研究利用電漿輔助化學氣相沉積(Plasma enhanced chemical vapor deposition ,PECVD) 製備超薄氫化非晶矽薄膜在粗糙化矽晶基板表面鈍化以應用於異質接面太陽能電池。研究中主要分為兩個部分，其一為利用調變射頻功率、氫稀釋比例、電極間距、基板溫度等製程參數探討對氫化非晶矽(a-Si:H)薄膜於粗糙化矽晶基板上鈍化特性影響，並在製程中搭配光放射光譜儀(OES) 與四極柱質譜儀(QMS)量測作為解析電漿物種及電漿反應機制，其二為經由不同晶片潔淨處理方式以優化薄膜與晶片介面間的品質，使得鈍化成效能更進一步提升。在分析薄膜結構特性上先以橢圓偏光儀量測薄膜厚度，再以少數載子生命週期來判斷薄膜鈍化品質優劣，最後經由快速熱退火處理作為進一步鈍化效果提升及確認與優化薄膜結構的依據。 研究結果顯示，透過OES和QMS電漿診斷確實有助於解析電漿物種及電漿反應機制，並在薄膜特性與鈍化品質分析上有所幫助，更能增加在製程分析上的準確性及提高製程穩定性與效率，因此在粗糙化矽晶基板上沉積氫化非晶矽薄膜製程參數中，我們可於H2/SiH4=7.3、射頻功率30W、製程壓力300mtorr、製程溫度300 ℃(實際溫度約為154 oC)的條件下得到約12nm 超薄氫化非晶矽薄膜，搭配選用適合的晶片處理方式提升介面品質可獲得最佳鈍化效果，少數載子生命週期可達到690μsec，Implied Voc值可達到約0.69V，相當於粗化矽晶表面復合速率可下降至12 cm/s的良好鈍化效果。 ;In this study, the intrinsic hydrogenated amorphous silicon (a-Si:H) thin films deposited on the textured silicon substrate for application in heterojunction with intrinsic thin layer (HIT) solar cell was prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD). The passivation quality of a-Si:H thin films was investigated by modulating the process parameters such as power, distance, dilution ratio, and substrate temperature. During the process, OES (Optical emission spectrometer) was used to diagnose the variation of plasma species, and QMS (Quadrupole mass spectrometry) was utilized to determine the concentration of free radicals in plasma. We changed different method of wafer cleaning to improve the interface between substrate and thin film. The thickness and the characteristics of thin film were measured and further analyzed by Spectroscopic Ellipsometer. The surface passivation quality of thin film was determined by photo-conductance lifetime tester. We also used annealing treatment to further improve the structure of a-Si:H thin films. The results show that integrated QMS and OES is indeed a way to help us to analyze the mechanism of plasma, and by adjusting the process parameters, the property of amorphous silicon (a-Si:H) thin films is determined. A high passivation quality of a-Si:H thin films on the textured silicon substrate was obtained under the conditions of H2/SiH4=7.3, power of 30W, working pressure of 300mtorr , substrate temperature of 300℃,and appropriate wafer cleaning. The effective lifetime of a-Si:H film increased to 690 μsec, the implied Voc increased to 0.69 V and the surface recombination velocity (SRV) was also reduced to 12 cm/s.
