應變矽/鍺之拉曼頻譜分析以及拉曼頻譜對微晶矽之應用

Raman Studies of Si, Ge and Raman Application of Microcrystalline Si

楊昱恆(Yu-Heng Yang)

指導教授 ： 劉致為

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.10606

摘要

本篇論文中研究主題在不同晶向的矽/鍺基板受到應變之情況下，其拉曼頻譜之改變以及多晶矽薄膜的結晶率之分析。由晶格動態理論所導出的特徵方程式，可以預測拉曼訊號和應變之間為線性的關係。根據選擇定則，入射之雷射光的電場極化方向會影響拉曼訊和應變之間線性關係的改變。換言之，在不同的極化方向下會有不同的程度的線性關係。以矽而言，在受到單軸或雙軸的伸張應變的情況下，拉曼訊號皆會紅移。然而，就晶向為(100)及(111)的鍺基板而言，在特定的極化方向的雷射入射時，受到單軸伸張應力會產生拉曼訊號藍移的現象。實驗的結果可合理的與理論結果一致，並且提出最佳化的彈性常數(p,q,r)。在薄膜結晶率的應用方面，介紹了分析微晶矽薄膜之結晶率的方法。並在實驗的過程中發現由雷射功率所造成的溫度會直接影響到拉曼頻譜的準確性。因此，在本論文中也探討雷射退火以及雷射升溫效應對微晶矽薄膜的影響。

關鍵字

應變 ； 應力 ； 拉曼 ； 結晶率

並列摘要

In this thesis, the strain effect on Raman spectrum of Si/Ge at different substrate orientations and the crystallinity of the microcrystalline silicon thin film are investigated. By the secular equation deduced from the lattice dynamical theory, the linear relationship between Raman frequency shift and strain can be predicted. According to selection rules, the polarization of the incident laser light will affect the Raman frequency shift. In other words, the linear relationship between Raman shift and strain will vary with distinct laser polarization. For Si, red-shift are observed under uniaxial and biaxial tensile strain. However, the unusual blue-shift of Ge Raman peak are observed at specific laser polarization on (110) and (111) substrate. The experimental data agree reasonably with the simulation results. Moreover, the optimized phenomenological constant (p, q and r) are proposed in this theses. The approaches that analyze the crystallinity of microcrystalline silicon thin film are introduced and studied. During the measurement of the microcrystalline silicon thin film, the temperature induced by laser power will influence the Raman spectrum. Thus the thermal effect such as laser annealing and laser heating are discussed.

並列關鍵字

Strain ； Stress ； Raman ； Crystallinity

參考文獻

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