鎳矽化合物誘發多晶矽薄膜側向結晶及其顯微結構觀察

Abstract

本論文的目的是研究鎳矽化合物誘發非晶矽低溫結晶以及側相結晶的 現象。使用熱蒸鍍機共蒸鍍鎳矽靶材於預先製作好圖案之試片上，形成鎳 矽鍍層/非晶矽層/SiNx/玻璃的排列方式之試片，並得蒸鍍之最佳製程參數 為靶材距離坩堝5 公分、鎳矽靶材重量比2 比1。 將試片封管進行真空退火，發現鎳矽化合物確實能誘發非晶矽結晶且得到 較快之側向結晶速率分別為550℃平均速率為3.46μm/hr、560℃平均速率 為6.58μm/hr、570℃平均速率為9.07μm/hr。由XRD 分析得知，試片經退 火後產生的多晶矽主要為{111}擇優取向，此結果與SEM 觀察到的長條狀擇 優取向晶粒相符合。由拉曼分析得知試片在550℃退火兩小時即可產生誘發 結晶的效果，而結晶矽峰值位置(518.21 cm-1) 稍偏離520cm-1之現象來自於 奈米級晶粒之效應 。由AFM 分析結果，本實驗依熱處理條件不同，得到的 晶粒直徑約在100-200nm 之區間，此較小的晶粒直徑與大量的鎳矽化合物 貢獻較多的成核點有關聯。

In this research, crystallization of a-Si films on glass substrate using Nickel disilicide (NiSi2) induced crystallization technique at low temperature and its corresponding lateral crystallization behavior has been studied. Nickel silicide layer was deposited on the pre-patterned sample by co-evaporation and sample was in the Nickel silicide / a-Si / SiNX / glass sequence. The optimum process condition was that distance from sample to crucible in 5cm and the weight ratio of Nickel target to Silicon target was in 2:1.After the sample was encapsulated and annealed, the lateral crystallization rate was 3.46-m/hr􀇵6.58-m/hr􀇵 9.07-m/hr at 550􀊚􀇵560 􀊚and 570􀊚 respectively. From XRD analyses, the poly-Si grains were in the {111}-preferred orientation which was consistent with the SEM observations. From Raman spectroscopy, the Nickel disilicide induced poly-Si after annealing at 550􀊚 for 2 hours and the slight offset of poly-Si Raman signals from 520cm-1 was arisen from the nano-size crystallite effect. From AFM analyses, the Poly-Si crystallite size was 100-200nm depending on the annealing process and the abundant Nickel disilicide acting as more nucleation sites caused the small size of Poly-Si crystallite.