單晶氧化鈧磊晶成長在矽基板(111)方向其結構性質探討

High-quality thin single-crystalline Sc2O3 films grown on Si(111)

周欣儀(Hsing-Yi CHOU)

指導教授 ： 洪銘輝

國立清華大學/工學院/材料科學工程學系/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00483

摘要

在本論文中，利用分子束磊晶與電子束蒸鍍的方式在超高真空下成長不同厚度的單晶Sc2O3薄膜於(111)矽基板上。並以高能電子繞射系統(RHEED)、高解析度X光繞射(XRD)、X光反射率(XRR)和高解析度穿透式電子顯微鏡(HRTEM)等系統來分析樣品成長過程變化、表面平坦度、晶格特性、薄膜結構、晶界情形。
經由量測結果，此磊晶氧化鈧薄膜具有立方晶相結構與矽基板界面為cubic-on-cubic的方向關係，並具有極佳結晶性及平整無任何二氧化矽或其他矽氧化物的介面。結晶方向則為氧化鈧[111]平行矽基板[111]成長，平行膜面方向則由phi scan發現相對旋轉了60度，並經由電子繞射證實。 在高解析度穿透式電鏡下觀察到界面有週期性的差排存在，為探討Sc2O3/Si(111)界面差排的平均距離，以及界面關係結構。我們嘗試將解釋晶界的理論：Bollmann O-lattice理論，用來解釋界面結構及預測界面差排的平均距離。差排的應變場相當局部化，且是由一組交錯的差排網路貢獻而來。在氧化鈧與矽基板兩個 {111}面的會合處有 dislocation 出現，其 Burgers vector 為1/
2<112>;此外，我們也發現到由氧化鈧與矽基板相疊而形成的Moire fringe。

關鍵字

分子束磊晶 ； X光繞射 ； 氧化鈧 ； 穿透式顯微鏡

並列摘要

Sc2O3 films had been found to be epitaxially grown on Si (111) substrate with different thickness. With electron beam evaporated from a high-purity Sc2O3 source in UHV (a molecular beam epitaxy (MBE) approach), we got good crystallinity Sc2O3 film on silicon substrate. The in-situ reflection high energy electron diffraction (RHEED) was used to monitor the surface of the sample during the growth process. Structural and morphological studies were examined bysingle x-ray diffraction(XRD), and high-resolution transmission electron microscopy(HRTEM). The film thickness has been studied using low-angle x-ray diffraction (XRR) and cross-sectional TEM.
The Sc2O3 films grown in our MBE system have a cubic phase with a very uniform thickness and a highly structural perfection, even for films as thin as 1.5 nm. Moreover ,without capping amorphous silicon to protect the Sc2O3 film, there has no interfacial layer exist in the interface. The film normal was found to be <111>, which is well aligned with the Si substrate normal. From the phi scan the in plane relation was rotated by 60 degree, and was proved by electron diffraction. To describe the periodical dislocation in the interface, we quoted Bollmann O-lattice theory, and estimated of the spacing between dislocations. We are surprised with large lattice mismatch (up to 9.3%) Sc2O3 still can form one domain crystalline film.

並列關鍵字

molecular beam epitaxy (MBE) ； x-ray diffraction (XRD) ； Sc2O3 ； transmission electron microscopy (TEM)

參考文獻

chapter 1

1 electronics, Volume 38, number 8, April 19, 1965

2 Comparison of wide-bandgap semiconductors for power electronics applications. B.Ozpineci, L. M.

Tolbert, Oak Ridge National Laboratory

4 M. Trivedi, K. Shenai, The 33rd Annual Meeting of IEEE Industry Applications Society, 1998, pp.