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X-ray absorption fine structure analysis of functional thin films

功能薄膜的X射线吸收精细结构分析

基本信息

批准号：
08454222
负责人：
WATANABE Iwao
金额：
$ 0.9万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

Some of the thin films of a few micrometers in thickness are important materials for magnetic information storage devices, sensors, surface coating for optical devices, plating for corrosive metals, etc. In order to improve the functions of these thin films the information of their atomic scale structures is crucial. However, it is often difficult to obtain structural information of very thin films deposited on thick substrates. The purpose of this research is to investigate these thin films by X-ray absorption fine structure (XAFS) analysis which is known to be useful for studying the local atomic structure. XAFS is normally obtained by transmission method, thus it is difficult to be applied to thin films on thick substrate. Here the XAFS spectra are obtained by total-conversion electron-yield method (TCEY). Since the mean free path of Auger electrons is less than a few micrometers, TCEY-XAFS method is useful for the study of surface materials.TCEY-XAFS of deposited thin films of SrTiO_3 on single crystals, LaAIO_3 and MgO, as substrates have been studied. From the XAFS signal intensities for several samples with different thicknesses, Sr K- and Ti K-edge detecting depths are found to be 300 nm and 30 nm, respectively. The EXAFS analyses for Sr and Ti in thin films concluded that the local structure of Sr changes with the film thickness, but that of Ti does not.Amorphous iron silicates or iron nitrides are interesting magnetic materials. They can be deposited on glass by sputtering method. Their local structures are compared with those in bulk samples. The TCEY-XAFS spectroscopy is especially suitable for these amorphous deposited materials.

一些厚度为几微米的薄膜是磁信息存储器件、传感器、光学器件表面涂层、腐蚀性金属电镀等的重要材料。为了提高这些薄膜的功能，其原子尺度结构的信息至关重要。然而，通常很难获得沉积在厚衬底上的非常薄的膜的结构信息。本研究的目的是研究这些薄膜的X射线吸收精细结构（XAFS）分析，这是已知的是有用的研究局部原子结构。XAFS通常采用透射法获得，难以应用于厚衬底上的薄膜。XAFS谱是用总转换电子产额法（TCEY）得到的。由于俄歇电子的平均自由程小于几微米，TCEY-XAFS方法对表面材料的研究是有用的。从XAFS信号强度为几个样品具有不同的厚度，Sr K-和Ti K-边缘检测深度被发现是300 nm和30 nm，分别。对薄膜中Sr和Ti的EXAFS分析表明，Sr的局域结构随薄膜厚度的变化而变化，而Ti的局域结构不随薄膜厚度的变化而变化。它们可以通过溅射方法沉积在玻璃上。它们的局部结构进行了比较，在散装样品。TCEY-XAFS光谱特别适用于这些非晶沉积材料。