同步輻射技術在半導體材料之研究

Abstract

同步加速器光源是二十一世紀尖端科學研究不可或缺的實驗利器，已廣泛應用在材料、生物、醫藥、物理、化學、化工、地質、考古、環保、能源、電子、微機械、奈米元件等基礎與應用科學研究，因而被稱為現代的「科學神燈」。 本文主要討論同步輻射技術在半導體材料上的研究，共分五個章節，第一章為同步輻射的介紹，包含何謂同步輻射、同步輻射的歷史、同步輻射的產生源、同步輻射光源的特性、如何產生同步輻射? 以及同步輻射的應用。第二章為本文中使用到的實驗設備以及實驗原理的介紹，包含光激螢光、X光繞射、X光吸收光譜。第三章主要是以薄膜的氮化鋁鎵以及氧化鋅鎂做粉末X光繞射光譜以及室溫與變溫的光激螢光光譜之數據分析。 第四章以同步輻射的X光繞射光譜為主，一開始先介紹我們實驗室使用的兩套晶格的資料庫，無基晶格結構資料庫(ICSD)以及國際繞射資料庫(ICDD)，再以圖示說明如何使用結構分析系統(GSAS)軟體去分析我們在國家同步輻射中心光束線01C粉末X光繞射儀上，所做的量測數據，而在第四章文中分析的X光繞射光譜數據包含氮化鋁生長在藍寶石基板、塊材的氮化鋁、矽鍺矽材料、立方碳化矽生長在矽基板以及氧化鋅生長在藍寶石基板，最後將以上五種樣品的同步輻射粉末X光繞射光譜用結構分析系統軟體做結構精算後，結果整理成圖四之十到圖四之二十以及表格四之五，而在本章中，我們也遇到了一個問題是:在所有的量測數據中得到氮化鋁及氧化鋅的晶格結構為烏采結構，但是在我們做結構精算的結果中卻得到都是立方晶體的結構，為何如此?我們猜測可能是因為同步輻射光源的高能量入射光導致晶體的結構轉相。 而第五章以同步輻射的X光吸收光譜為主，一開始先簡單的介紹二六族元素化合物鉻化硒碲、碲化鋅錳及碲化鉻鋅的應用，再以圖示說明如何使用X光吸收光譜的分析軟體雅典娜(Athena)以及亞特密斯(Artemis)去分析我們的實驗數據，其中包含塊材的鉻化硒碲、碲化鋅錳、碲化鉻鋅以及薄膜的氮化鎵、氧化鋅、二氧化鉿分別都生長在矽基板上。結果發現，上述化合物皆因為某一元素含量的改變，造成較小尺寸原子取代較大尺寸原子在晶格中的位置，因而改變原子間的鍵長及配位數，所以我們可以藉此了解特定元素其區域結構。

During the past decade, synchrotron light sources have become indispensable tools for advanced scientific research. Synchrotron light is used widely in basic and applied research throughout the fields of materials science, biology, medicine, physics, chemistry, chemical engineering, geology, archeology, environmental science, energy, electronics, micro-mechanical engineering, and nanotechnology. For this reason synchrotron light sources have been coined 'magic lamps of science'. This thesis will focus on synchrotron radiation technology studies of semiconductors and heterostructures. The thesis consists of five chapters: in chapter one, we introduce the synchrotron radiation, including the explanation, history, sources, properties, production and applications of synchrotron radiation. In chapter two, we introduce the experimental instruments and the theoretical background, including photoluminescence (PL), x-ray diffraction (XRD), and x-ray absorption (XAS). In chapter three, we analyze the powder XRD spectrums and the temperature dependent of PL spectrums of the thin film AlGaN and MgZnO samples. In chapter four, we discuss the synchrotron radiation powder XRD. In the beginning of chapter four, we introduce two crystallographic databases, Inorganic Crystal Structure Database (ICSD) and International Centre for Diffraction Data (ICDD) which are usually used by our laboratory members. We illustrate the methods of analyzing the XRD data by General Structure Analysis System (GSAS) program with pictures and measure these XRD data by using the experimental instrument for synchroton radiation X-ray powder diffraction at beamline 01C2 of the National Synchrotron Radiation Research Center (NSRRC). The analyzed XRD data include AlN on sapphire substrate, bulk AlN, Si-Ge-Si, 3C-SiC on sapphire substrate and ZnO on sapphire substrate. Then, we refine the crystal structure of five kind samples above mentioned by GSAS. In this chapter, we encounter a problem: we know that the crystal structure of AlN and ZnO are wurtzite in our all measurement. Nevertheless, the result shows that crystal structural refinement is cubic system. Why? We guess that the crystal structure is transformed because the energy of the incident synchrotron radiation x-ray (28keV) is too high. In chapter five, we discuss the synchrotron radiation XAS. We introduce the applications of II-VI compound materials, CdSeTe, ZnMnTe, and CdZnTe. We measure these samples that include CdSeTe, ZnMnTe, CdZnTe bulk and thin film GaN/Si, ZnO/Si, HfO2/Si by using the Athena and Artemis program. The results show that the various compositions of certain element in the above compound materials cause the small-size atoms substitute the big-size atoms in the crystal lattice, so the bond length and coordination number between atoms are changed. Therefore, we can understand the local structure of the specific elements.