Modifications to the microhardness, adhesion, and resistivity of sputtered TiN films by ion implantation

Abstract

This study reports on modifications in surface mechanical and electrical properties of TiN films by heavy ion implantation. TiN films deposited by direct sputtering and reactive sputtering on different substrates were implanted with Kr+ to doses from 5×1014 to 5×1016/cm2. The energy of the implanted ions was chosen on the basis of calculated projected range of the ions in TiN and the film thickness. The thickness and composition of TiN films were measured by Rutherford backscattering and 14N(d,α)C12 nuclear reaction. Films directly rf-sputtered from TiN target had a deposition rate of 40 Å/min and showed no appreciable change of variation in N2 partial pressure, bias potential, and substrate temperature. However, the deposition rate and film composition of reactively sputtered films were found to change with N2 pressure and substrate temperature. The structure of the as-deposited films were determined by electron diffraction. Films implanted with Kr+ exhibited increase in microhardness, adhesion, and resistivity. These increases were found to be dependent on the initial film composition and implanted ion dose. It is suggested that the changes in the surface properties may be explained on the basis of ion-induced diffusion between the atoms from the substrate and that from the films.