多層薄膜樣品之X光散射研究

本論文是利用X光反射率(X-Ray Reflectivity)、高解析X光繞射(High Resolution X-Ray Diffraction)與平面掃描(2-D Mapping)的研究方法，針對多層薄膜的樣品NSMO(Nd0.35Sr0.65MnO3)以及YBCO(YBa2Cu3O7)之結構加以分析與討論，兩種材料係以不同的順序成長於LAO(LaAlO3)基板上時的薄膜樣品結構，並且比較兩種不同成長順序的薄膜在其表面/介面粗糙度以及厚度。實驗結果發現NSMO與YBCO成長順序相反時，薄膜樣品因為堆疊順序的不同進而導致晶格排列出現較不一樣的情況。透過平面掃描，我們可以量測出基板LAO的品質，發現YBCO/NSMO/LAO該塊樣品之基板有twining的結晶情況，進而影響到往上成長的薄膜結構也產生twining的情況發生，與該樣品針對反射率量測結果為粗糙度較大的情況相互呼應，因此，了解到基板之結晶品質對薄膜樣品成長時所造成的影響性：最後，在phi-scan的測量上發現NSMO/YBCO/LAO樣品之薄膜結構具有四重的對稱性，而YBCO/NSMO/LAO因為基板的問題，導致在結構對稱性上出現瑕疵。

關鍵字

X光繞射； X光反射率； X光高解析散射；平面掃描

並列摘要

This dissertation is discussing the study of multilayer thin films structure by using X-Ray Reflectivity (XRR), High Resolution X-Ray Diffraction (HRXRD) and 2D-mapping. XRR and HRXRD are used to probe the structural information on both NSMO/YBCO/LAO and YBCO/NSMO/LAO multilayer thin film for their thickness and roughness on surface and between interfaces. The lattice arrangement of NS/YB and YB/NS was found to be changed due to deposition sequence. By using 2-D mapping, the quality of substrate LAO was measured by identifying presented crystal twinning. On YBCO/NSMO/LAO multilayer thin film, crystal twinning was observed within the structure as well as its substrate LAO. It was suggested that the twinning on substrate will cause twining on the film which grows on it. This is further confirmed by the high roughness result from XRR measurements. From phi-scan, NSMO/YBCO/LAO shows orthorhombic symmetry, and YBCO/NSMO/LAO shows the defective symmetry due to the quality of substrate.

並列關鍵字

X-ray diffractiom ； X-ray reflectivity ； High resolution X-ray diffraction ； 2-D Mapping

參考文獻

【2】Mr. Scofield, Phys.Rev. 414 (2000)

& D. WERDER, “ Oxygen stoichiometry, superconductivity and normal-state

【6】L. V. Azaroff, “ Elements of X-ray Crystallography”, Chap.5, 7,9. New York:

McGraw-Hil (1968).

【7】B. D. Cullity and S. R. Stock, “Elements of X-ray diffraction”, Third edition,

國際替代計量

多層薄膜樣品之X光散射研究

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