Formation of Ni 2Si silicide in Ni/Si bilayers by ion beam mixing

Abstract

We have studied ion mixing in Ni–Si(1 1 1) bilayers using noble gas ions. Thin Ni films of 45 nm thickness, deposited on a Si (1 1 1) substrate, were irradiated with 175 keV Kr and 110 keV Ar ions at the same fluence of 4×10 16 ions/cm 2 at room temperature. The formation of the mixing and the elemental depth profile were investigated by Rutherford backscattering spectrometry. In the Ar irradiated sample, there was no structural change. On the other hand, we have noted the formation of Ni 2Si for the sample irradiated with Kr ions. X-ray diffraction measurements confirmed the formation of the Ni 2Si phase. The surface morphology of the Kr irradiated sample was also studied by scanning electron microscopy.