應用於太陽能電池之低溫多晶矽薄膜研究

Study of low temperature poly silicon for solar cells

林成(Chen Lin)

指導教授 ： 朱孝業 ； 翁敏航

崑山科技大學/工程學院/機械工程研究所/碩士(2006年)

摘要

本研究是利用多晶矽薄膜作為晶種並以兩階段退火，製備低溫多晶矽薄膜於太陽能電池，討論其微結構與電性之研究。此技術的特點在於所成長的多晶矽晶粒的橫向長度大於縱向的寬度。第一階段以500 °C持溫1小時，探討鋁金屬誘發再結晶。第二階段以不同退火溫度與時間分析鋁金屬誘發多晶矽之影響，完成之試片以X光繞射分析儀（XRD）進行結晶性分析，確認Si的結晶面存在與否，並以拉曼光譜分析相互印證，以場發射式電子顯微鏡（FE-SEM）觀察其表面結構與截面結構。以霍爾量測分析載子移動率，載子濃度，電阻率。最後並測試電流-電壓的特性已確定其暗電流的機制。實驗結果證實，經由兩階段退火的製程確實能有效降低多晶矽膜之製程溫度並獲得較佳的微結構組織。
退火溫度450 °C持溫15分鐘進行第二階段退火，成功研製膜厚1 μm的多晶矽薄膜且橫向晶粒大小約為3~5 μm。其中以500 °C持溫30分鐘退火之試件具有最高的載子移動率，其值為23.4 cm2/V.s。

關鍵字

太陽能電池 ； 多晶矽 ； 低溫多晶矽 ； 鋁金屬誘發再結晶

並列摘要

This study fabricates large grain low temperature poly-crystalline silicon film which can be applied to solar cell. The first annealed poly-crystalline silicon film is used as the seeding layer in the crystallization of the next thicker amorphous silicon film. The thickness of the silicon film is over 1 μm.
The annealing temperature is set at 500 °C and last for 1 hour in the first annealing stage. The crystallinity of the first annealed silicon film is discussed in this paper.
In the second annealing stage, two different annealing temperature (450 and 500 °C) and five different annealing time (15, 30, 60, 120 and 240 minutes) are chosen to see the influence of annealing temperature and time on the crystallization of poly silicon film. Leakage current and surface topography are also being studied.
XRD and Raman spectra analysis are used to identify the crystallinity of specimens made under different annealing time and temperatures. The surface and cross-section observation are observed and discussed via scanning electron micrographs. The I-V characteristic is tested to see the magnitude of leakage current of poly silicon film in our study.
Results show that two steps annealing does increase the XRD intensity with the increase of annealing time. The crystal size calculated by Scherrer equation shows that crystal size increases with the annealing time. The lateral grain size observed from SEM graph is about 3~5 μm. The maximum carrier mobility obtained in this study is about 23.4 cm2/V.s.

並列關鍵字

solar cells ； aluminum induced crystallization ； low temperature poly silicon ； poly-crystalline silicon

參考文獻

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