Thin film Rutherford backscattering spectrometry

The remaining work discusses two techniques in thin film analysis, Rutherford backscattering spectrometry (RBS) and X-ray diffractrometry with emphasis on strain measurements. Rutherford backscattering spectrometry is illustrated with analysis of silicide formation as an example of thin film reactions. Silicon-germanium-carbon films serve as an example of strain calculations. 

Rutherford backscattering spectrometry analysis determines how the composition varies as a function of depth and is used to characterize thin films and thin film reactions. During ion-beam analysis, the incident particle (typically a proton or helium ion) penetrates into the thin film and undergoes inelastic collisions, with target electrons, and loses energy as it transverses the sample. 

The essentially non-destructive nature of Rutherford backscattering spectrometry, combined with the its ability to provide both compositional and depth information, makes it an ideal analysis tool to study thin-film, solid-state reactions. In particular, the non-destructive nature allows one to perform in situ RBS, thereby characterizing both the composition and thickness of formed layers, without damaging the sample. Since only about two minutes of irradiation is needed to acquire a Rutherford backscattering spectrum, this may be done continuously to provide a real-time analysis of the reaction [6]. 

Baumann SM (1992) RBS Rutherford backscattering spectrometry. In Encyclopedia of materials characterization, surfaces, interfaces, thin films. Elsevier, Greenwich, pp 476-487... 

Jeynes, C., Barradas, N.P., Szilagyi, E., 2012. Accurate determination of quantity of material in thin films by Rutherford backscattering spectrometry. Anal. Chem. 84, 6061—6069. 

Various methods of analyzing surfaces for chanical composition and physical texture. Electron spectroscopy for chemical analysis and Auger analysis [19] are techniqnes that have been used to identily chemical species in thin films. In Rutherford backscattering spectrometry incident He ions are scattered elastically by nuclei. The energy spectrum thus obtained can... 

The application of ion beam analysis techniques to determine pore size and pore volume or density of thin silica gel layers was first described by Armitage and co-workers [114]. These techniques are non-destructive, sensitive and ideally suited for the analysis of thin porous films such as membrane layers (dense support is needed for backscattering). However, apart from a more recent report on ion-beam analysis of sol-gel films [115] using Rutherford backscattering and forward recoil spectrometry, ion beam techniques have not been developed further despite their potential for membrane characterisation. This is probably due to the limited availability of ion beam sources, such as charged particles accelerators. 

In addition to these characterization tools, surface analytical techniques such as surface matrix-assisted laser desorption ionization (Surface MALDI) mass spectrometry, Rutherford backscattering spectroscopy (RBS), and near-edge X-ray absorption fine stmcture spectroscopy (NEXAFS) are used to obtain structural and chemical details about surface thin films. Surface MALDI, also known as MALDI-ToF MS (see Section 5.4.2), offers high mass resolution for analyzing surface films and molecular layers using the m/z of various ions generated from the sample surface (mixed with an... 

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