II-VI及III-V族化合物半導體之紅外光譜研究

Infrared spectroscopic studies of II-VI and III-V compound semiconductors

侯復鐘(Fu-Chung Hou)

指導教授 ： 馮哲川

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.10702

摘要

光學量測對於分析半導體材料具有很重要的地位，尤其是對於材料的結構、特性，甚至是物理機制。而近幾年的半導體材料，由於它的材料特性非常適合應用在現今生活的電器設備用品上，譬如：發光二極體、積體電路原件…等，所以被廣泛而且深入的研究，縱使已經有不少上市產品應用半導體為材料，但是仍然有許多的問題與困難需要解答與突破，因此，我們將針對目前的許多挑戰做研究。
拉曼散射與紅外光譜是在研究半導體材料的晶格振動，我們可以藉由晶格的振動來判斷研究的材料或樣品的品質和成分，由於拉曼散射實驗與紅外光譜是非破壞性的光學量測技術，非常的方便且不需繁雜的事前準備或樣品處理，所以我們著重二者的應用，將所研究的樣品經由拉曼散射實驗與紅外光譜做初步的瞭解與分析，可以幫助我們在樣品的結構、成長或各種變因上做調變，有效而且快速的提供正確且有用的資訊。
此外，我們還會使用各種不同的光學量測系統得到更多的材料特性，進而得出相互驗證的結果，例如使用光激發螢光(PL)量測系統可以快速又可靠的得到材料中能階結構與載子躍遷行為，也是一個有力又無破壞性的技術，而搭配上螢光激發光譜(PLE)將可得到更完善的能隙或雜質能階譜線。傅氏轉換紅外線光譜儀(FTIR)則可以判斷長晶薄膜的厚度，樣品中是否含有雜質，並將其配合拉曼實驗可以得到完整的晶格振動譜線；X光繞射儀(XRD)就是利用X光進入晶體時，會被原子散射，當存在某種相位關係(相位差)兩個或兩個以上散射波相互疊加後，就會產生繞射現象。偵測器收集到繞射訊號強度，得到待測樣品的繞射圖譜，此繞射圖譜一般來說是以繞射強度對繞射角作圖，將此繞射圖譜經過結晶面標定過程後，便可得到樣品的結晶結構；X光光電子能譜術(XPS)，或稱之為化學分析電子能譜術(ESCA)是分析材料表面的電子結構與化學成分之重要方法之一。除了有較高的表面靈敏度及較高的化學分析能力，最重要的是光子對於物質的破壞性較低。因此，能被廣泛的應用於微電子元件的研究，如薄膜間因為不同製程階段的材質交互反應所引發的能帶偏折、能帶差位、以及化學能位移等物理量的量測。

關鍵字

紅外光譜 ； 反射率

並列摘要

A series of optical characterization techniques, including Raman scattering, Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL), photoluminescence excitation (PLE), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS) were employed to assess II-VI and III-V compound semiconductors. In this thesis, we study the optical properties, especially on Raman scattering and FTIR, of InSb bulk, Metalorganic magnetron sputtering (MOMS)-grown InSb films on GaAs substrates, MOMS-grown GaSb films on GaAs substrates, grown InGaAs films on InP substrates, HgMnTe bulk, CdSeTe bulk, CdZnTe bulk, CdZnMnTe bulk, CdMnSeTe bulk, and molecular beam epitaxy (MBE)-grown CdTe films on InSb substrates, and so on.
We got their fitted parameters through fitting with dielectric function of these semiconductors their far-IR spectra. The dielectric constant, the mobility, the carrier concentration of these samples and TO phonon peaks, damping constant, and oscillator strength of TO phonon in these samples were obtained by simulating their far-IR spectra. Measured at two temperatures, 80K and 300K, the far-IR spectra present the TO phonon peaks have a blue shift with the decreasing temperature.
We have two series samples grown by MOMS; grown InSb films on GaAs substrates and grown GaSb on GaAs substrates. Their far-IR spectra have been shown and studied in chapter 4. Especially the MOMS-grown GaSb on GaAs substrates reveals the existence of a GaSb-GaAs intermixed layer near the interface.
The far-IR spectra of bulk Hg1-xMnxTe, CdSexTe1-x, and Cd1-xZnxTe with different x have been fitted. We observed their TO phonon peaks shift with increasing x. Series MBE-grown CdTe films on InSb substrates with different growth conditions have been studied. Their far-IR spectra at 300K are shown in Chapter 5. But advanced studies are needed.

並列關鍵字

FTIR ； reflectance ； II-VI ； III-V

參考文獻

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