近年來,為了提高金氧半場效電晶體的運算速度,作為載子通道的矽單晶材料已被形變矽鍺異質磊品或形變矽磊晶材料所取代。因此,鑑定此類形變磊晶材料與矽單晶基材的晶體不匹配度與鬆弛程度,便成為一個很重要的課題。由於高解析度多品三軸繞射儀具備良好的光學模組,有效地提高在倒易空間量測上的解析能力,進而使得二維X光倒易空間圖譜技術成為鑑定異質磊晶材料的重要研究工具。本文將介紹X光倒易空間圖譜分析原理,高解析度多晶三軸繞射儀光學模組構造與X光倒易空間圖譜的操作流程,應變數值分析原理,最後舉例應用X光倒易空間圖譜鑑定不同形變矽鍺異質磊晶薄膜的分析結果。
Recently, single crystal Si channels in metal-oxide-semiconductor field effect transistors (MOSFETs) have been replaced with stained Si, SiGe and Ge channels in order to enhance electron or hole mobility in channel direction. Therefore, it is a significant issue to evaluate the strain relaxation and lattice mismatch in these strained silicon-germanium hetero-epitaxial layers. However, two-dimensional reciprocal space mapping (2D-RSM) employing the triple axis X-ray diffractometry have been considered to be a powerful technology to characterize the strain status of these kinds of materials. In this article, we describe the principle of 2D-RSM, the optic components in triple axis X-ray diffractometry, experimental procedures in detail, the principle of strain calculation, and finally illustrate the experimental results of a variety of strained silicon-germanium hetero-epitaxial layers using two-dimensional reciprocal space mapping technology.