應變矽/矽鍺能帶研究與螢光光譜分析

Optical characteristic of Si/SiGe heterostructure with strain in Si

許家桂(Jia-Guei Xu)

指導教授 ： 鄭鴻祥

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.00953

摘要

由於應變矽在金屬氧化物半導體電晶體的通道中載子有高遷移率，所以近年來，應變矽/矽鍺異質結構受到廣大的注目，這將可利用在光電元件上。關於異質結構傳輸特性的研究已經被施行，不過能帶仍然少有研究成果。在這篇論文中，我們描述應變矽/矽鍺異質結構的光致發光螢光，在量子井中的激子已用實驗觀測到，這將對應出應變矽的能帶圖，從分析中，能帶排列可以被決定。在這論文中有四個章節:第一章: 分子束磊晶以圖示介紹，矽和鍺的能帶結構也簡單介紹了。在樣品中的高溫緩衝層和低溫緩衝層被描述了，矽和鍺兩者在能帶上都是非直接能隙的材料，色散關係和等能圖也以圖解方式介紹，如此電子和電洞在動量空間的行為將可以輕易地被知道。第二章: 應變效應、矽鍺異質結構的帶排列、拉曼散射、x射線繞射、轉移矩陣和激子將會被說明，本章的內容對於分析能帶結構和電子躍遷是非常有幫助的。第三章: 實驗將會被簡短介紹，光致發光實驗儀器架設已經以圖示介紹。在光致發光螢光光譜中，錯位線(D1、D2、D3、D4)和聲子線(NP、TA和TO 聲子)，這些線都會在光致發光螢光光譜中找到。第四章: 量子井內的電子躍遷將顯示在光致發光螢光光譜中，在量子井中，離散的能階位置已經用轉移矩陣解出了，實驗的數據和理論分析的結果也被比較。最後，激子躍遷的反磁位移和電子躍遷模式(delta2-hh或delta4-hh)將被討論。

關鍵字

應變 ； 矽 ； 鍺 ； 矽鍺 ； 量子井 ； 螢光 ； 異質結構 ； 能帶 ； 磁場

並列摘要

Abstract
Silicon/silicon germanium (Si/SiGe) heterostructures with strain presented in the Si layer has attracted great attention in recent years due to its high mobility in the channel of Metal Oxide Semiconductor Field Effect Transistor (MOSFET). The structure has been employed in optoelectronic devices. Intensive research has been performed in concerning the transport properties of the heterostructure. Nevertheless, the band profile has been less investigated.
In this thesis, we report photoluminescence on SiGe/Si with strained presented in the Si layer. Exciton in quantum wells is observed in our measurement. These features reflect the band profile of strained Si. From the analysis, the band alignment of the system is determined.

This thesis is organized as four chapters described as followings:
Chapter 1: the growth technique of Molecular Beam Epitaxy (MBE) is illustrated. The mechanism of high temperature buffer and low temperature buffer is described. The band structure of both silicon and germanium are introduced briefly. Silicon and germanium are both indirect bandgap materials, and are illustrated by dispersion relation figures and constant energy surface figures. States of electrons and holes in k space can be known easily.
Chapter 2: the strain effect, band alignment of Si/SiGe heterostructures, Raman scattering, X-ray diffraction, Transfer Matrix method, and exciton are explained. The content of this chapter is helpful to analyze band structures and understand exciton transitions.
Chapter 3: PL measurement is explained briefly, and PL experimental instrument setup is illustrated. In PL spectra, there are dislocation lines (D1, D2, D3, and D4) and phonon lines (no phonon line, TA phonon line, and TO phonon line). They can be measured in the PL experiments.
Chapter 4: Exciton transition in the quantum wells are found in PL spectra. The band diagrams of the samples are plotted. The quantized energy levels in the quantum wells are solved by Transfer Matrix method. The experimental data and theoretical analysis are compared. Finally, the diamagnetic shift of exciton transition and which band transition (delta2-hh or delta4-hh) are discussed.

並列關鍵字

PL ； photoluminescence ； strain ； silicon ； germanium ； SiGe ； quantum ； heterostructure ； band structure

參考文獻

Chapter1 References

[1] J M Hartmann, B Gallas, J Zhang, J J Harris, “Gas-source molecular beam epitaxy of SiGe virtual substrates: II. Strain relaxation and surface morphology”,

[2] Douglas J Paul, “Si/SiGe heterostructures: from material and physics to devices

[3] J. W. Matthews, “Defects associated with the accommodation of misfit between

crystals”, J. Vac. Sci. Technol., Vol. 12, No 1, Jan./Feb. 1975