Study of interdiusion in amorphous Si/Ge multilayers by Rutherford backscattering spectrometry A. Simon a, * , A. Csik b , F. P aszti c ,  A.Z. Kiss a , D.L. Beke b , L. Dar oczi b , Z. Erd elyi b , G.A. Langer b a Institute of Nuclear Research, Hungarian Academy of Sciences (ATOMKI), P.O. Box 51, H-4001 Debrecen, Hungary b Department of Solid Sate Physics, Kossuth Lajos University, P.O. Box 2, H-4010 Debrecen, Hungary c KFKI-Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest, Hungary Abstract Amorphous Si/Ge multilayers of 10±40 nm repeat length were prepared by DC magnetron sputtering and annealed at 683 K. Rutherford backscattering spectrometry (RBS) with increased depth resolution was applied to study the intermixing of the elements. The interdiusion coecient was determined by measuring the intensity of the ®rst Ge peak in the RBS spectrum as a function of annealing time. An attempt was made to observe the theoretically predicted change of dimensions of the Si/Ge layers caused by the diusion asymmetry. Ó 2000 Elsevier Science B.V. All rights reserved. PACS: 61.43.D; 68.35.F; 68.65; 61.85 Keywords: Amorphous multilayer; Silicon±Germanium; Rutherford backscattering spectrometry (RBS); Interdiusion 1. Introduction Multilayers and superlattices are of consider- able industrial interest because of their speci®c properties and many promising areas of applica- tions in electronics or optics [1,2], etc. However, the multilayers as arti®cial, compositionally modulated materials are not equilibrium struc- tures. In particular, they have high interfacial density gradients and sucient atomic mobility even at moderated temperatures, hence changes in the composition pro®le are expected to occur. Thus, investigation of the thermal stability and understanding of the factors controlling structural changes of these multilayers is very important for the interpretation of their operation and predic- tion of their lifetime. Concerning amorphous Si/Ge multilayers, the mechanism of their diusional homogenisation is still an open question. First of all the diusional asymmetry [3] and the strong pore formation during the diusional mixing [4] are the most im- portant factors indicating the need of a better understanding of the above process. Nuclear Instruments and Methods in Physics Research B 161±163 (2000) 471±475 www.elsevier.nl/locate/nimb * Corresponding author. Tel.: +36-52-417-266; fax: +36-52- 416-181. E-mail address: a.simon@moon.atomki.hu (A. Simon). 0168-583X/00/$ - see front matter Ó 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 9 9 ) 0 0 9 6 6 - 0