Swift heavy ion-induced interface mixing in a Si-Nb thin film system

In this work, we report the study of swift heavy ion-induced mixing at the interface of an a-Si/Nb/a-Si (a-Si = amorphous silicon) thin film system at different fluences using two different characterization techniques: secondary ion mass spectroscopy and Rutherford backscattering spectrometry. The depth profiles of the samples of this system showed significant changes in the interface region when irradiated by 120 MeV Au ions. The fluence range was varied from 1 x 10(13) to 1 x 10(14) ions/cm(2). Significant interface mixing has been observed in this range and was found to increase linearly with the increase in the ion fluence. Atomic force microscopy of the samples was also performed to confirm that there is no significant contribution of surface roughness. Mixing has been quantified in terms of mixing rate (k). This high energy-induced mixing effect has been explained in the framework of the thermal spike model which verifies the hypothesis of melt-phase diffusion across the interface.