摘要

國立清華大學物理研究所學位論文
題目 : 三光布拉格表面繞射方法研究Si0.8Ge0.2/Si之介面應力變化
學生 : 魏永成
指導教授 : 張石麟

在半導體的製程中，介面應變(Interfacial strain)有著改變元件特性的影響，人們利用晶體所受之應變來改善元件效能，因此我們將進行介面應變的研究。本實驗主要利用X光三光布拉格表面繞射(X-ray Three-Beam Bragg-Surface Diffraction，BSD)實驗方法，入射X光同時激發矽(Si)基板與矽鍺(SiGe)薄膜的繞射光，收取矽基板與矽鍺薄膜二階繞射光來分析介面應力之變化。
本實驗在國家同步輻射研究中心(National Synchrotron Radiation Research Center，NSRRC) BL17B1光束線進行，所使用的能量為12KeV。首先利用掠角繞射與布拉格繞射研究Si0.8Ge0.2/Si的晶體品質；接著進行三光布拉格表面繞射實驗來研究Si0.8Ge0.2/Si的介面應變；本實驗在所選取之二階繞射反射面微調樣品方位角ф±〖0.02〗^°同樣收取三光布拉格表面繞射實驗數據，以研究樣品在所選取二階繞射反射面在樣品方位角ф±〖0.02〗^°之介面應變。
本實驗樣品是委託國家奈米實驗室(NDL)使用分子磊晶(MBE)製程製作，薄膜矽鍺比例為Si0.8Ge0.2，樣品薄膜厚度為47.24nm、75.55nm兩塊。
實驗分析結果發現薄膜越厚，薄膜垂直晶軸的應變越大。且與之前吳庭瑋學姊[4]的三光布拉格表面繞射圖比較得知SiGe和Si之間的震盪訊號，是因為薄膜干繞射產生的現象。

ABSTRACT
Investigation of Interfacial Strains in Si0.8Ge0.2/Si
Using Three-Beam Bragg-Surface Diffraction

Yong-Cheng Wei, Advisor : Professor Shih-Lin Chang
Master of Physics,
National Tsing Hua University, Hsinchu, Taiwan

In the manufacturing processes of semiconductor, interface strains play an important role in changing the device characteristics. Most importantly, strain is used to improve the device performance and yet broaden their applications. Therefore, here we focus on interfacial strains in Si0.8Ge0.2/Si using three-beam Bragg-surface diffraction(BSD).
This experiment was carried out in the National Synchrotron Radiation Research Center at BL17B1 beam line. The energy of incident X-rays used is 12KeV. First, we study the crystalline quality of Si0.8Ge0.2/Si samples using grazing incidence X-ray diffraction and Bragg’s diffraction. Afterwards, we measure the interfacial strains of Si0.8Ge0.2/Si using three-beam Bragg-surface diffraction(BSD). By slightly changing the azimuth angle ф±〖0.02〗^° of the selected second-order surface diffraction, variation of interfacial strains are obtained.
The sample is a germanium silicide film grown on a silicon substrate, where the SiGe films are about 47.24nm and 75.55nm thick and Si V.S. Ge is 0.8:0.2.
It is found that when the germanium silicide film becomes thicker, the interfacial strains along the c-axis increases. In comparison of the previous results

Ting-Wei Wu[4], the undulating intensity signals in between SiGe and Si peaks is due to the interference of the surface diffraction at the interface in Three-Beam Bragg-Surface Diffraction experiment.

參考文獻

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