Research activity

Analytical applications

Materials science

Contact: Alíz Simon, a.simon (at) atomki.hu

The Oxford-microbeam facility makes it possible to collect the analytical data point by point with a focussed ion beam. Beside the full area, we can collect spectra belonging to a specific region or even a point. This way, we have the analytical information with a high lateral resolution [38], actually defined by the beam spot size. On the basis of the micro-RBS spectra, elemental maps are also generated in order to investigate the lateral elemental distribution. This method is very fruitful in studying the surface roughness [39] of thin samples. RBS is especially useful when not only the composition of the samples but also their depth profiles are to be determined in the first few µm. We can even demonstrate the elemental depth distribution in tomographic images [40]. We have a wide experience in investigation of thin films [41], multilayers [42], surface roughness [43], and diffusion profiles [44] with an RBS microbeam.


Si micro-RBS elemental map of an ion-bombarded top layer of a Si/Cr multilayer sample. Full scan of 1250 x 1250 µm2. Approximately a quarter of the crater is seen. The top Si layer thickness is about 5 nm in the bottom of the crater while it increases up to 37 nm in the virgin area. It is seen that the bottom of the crater is not flat.


Tomographic image along the diagonal. Energy of the backscattered particles is represented as a function of the position. Si: bottom three lines, Cr: top three lines. The separated Si and Cr signals belonging to the different layers and the missing Si counts, due to the Si removal, causing energy shift of the underlying layers are well seen.

References:

[38] A. Simon, T. Csákó, C. Jeynes, T. Szörényi: High lateral resolution 2D mapping of B/C ratio in boron carbide films, Nucl. Instr. and Meth. B 249 (2006) 454

[39] A. Simon, Z. Kántor: Micro-RBS characterisation of the chemical composition and particulate deposition on pulsed laser deposited Si(1-x)Gex thin films, Nucl. Instr. and Meth. B 190 (2002) 351

[40] A. Simon, F. Pászti, I. Uzonyi, A. Manuaba, I. Rajta, Á.Z. Kiss: Observation of surface topography using an RBS microbeam, Nucl. Instr. and Meth. B 136 (1998) 344

[41] A. Simon, Z. Kántor: New challenges in Rutherford backscattering spectrometric (RBS) analysis of nanostructured thin films, Invited paper in Nanotechnology. Ed. by R. Vajtai, X. Aymerich and L.B. Kish Proceedings of SPIE Vol. 5118 (2003) 179

[42] A. Simon, A. Sulyok, M. Novák, G. Juhász, T. Lohner, M. Fried, A. Barna, R. Huszank, M. Menyhárd: Investigation of an ion-milled Si/Cr multilayer using micro-RBS, ellipsometry and AES depth profiling techniques, in press, Nucl. Instr. and Meth. B (2009), doi:10.1016/j.nimb.2009.03.052

[43] A. Simon, Z. Kántor, I. Rajta, T. Szörényi, Á.Z. Kiss: Micro-RBS as a technique for the determination of the surface topography of Bi film prepared by pulsed laser deposition, Nucl. Instr. and Meth. B181 (2001) 360

[44] J. Slotte, A. Laakso, T. Ahlgren, E. Rauhala, R. Salonen, J. Räisänen, A. Simon, I. Uzonyi, Á.Z. Kiss, E. Somorjai: Influence of surface properties on the diffusion profiles obtained by Rutherford backscattering spectrometry, Journal of Applied Physics 87 (2000) 140