Effects of stress on electrical transport properties of nickel silicide thin layers synthesized by Ni-ion implantation

Abstract

Nickel disilicide layers were prepared by nickel ion implantation into silicon substrates using a metal vapor vacuum arc ion source at various beam current densities to an ion dose of 3×1017 cm−2. The as-implanted and annealed samples were characterized by using Rutherford backscattering spectrometry, x-ray diffraction, micro-Raman spectroscopy, electrical resistivity, and Hall-effect measurements. Residual stress in the NiSi2 layers was determined using the sin2 ψ method of x-ray diffraction, assuming that a biaxial stress state exists in the layers and that the elastic properties of the layers are isotropic. The temperature dependence of the sheet resistivity and the Hall mobility from 30 to 400 K showed peculiar peak and valley features varying from sample to sample, depending on the preparation conditions. However, after annealing, the differences between samples seemed to have diminished in that they all showed similar shapes in both the sheet resistivity versus temperature and the Hall mobility versus temperature curves. It was also shown that the electrical transport properties were highly correlated with the stress in the layers.