High fluence implantation of nitrogen into titanium: Fluence dependence of sputtering yield, retained fluence and nitrogen depth profile

Abstract

Nitrides are formed by high-fluence nitrogen implantation into various metallic targets, and their surface properties are improved. Among them, titanium nitride formation is of great interest in a wide range of technological applications. For nitrogen implantation into Ti with implantation energies of 10 keV to 1 MeV and fluences up to 1 × 10 19 ions cm −2, the fluence dependence of sputtering yield, retained fluence and nitrogen depth profiles as well as the implantation energy dependence of saturated thickness of a nitride layer were calculated by computer simulation using the “dynamic SASAMAL” code with various values of threshold displacement energy ( E d) and surface binding energy ( E s). The calculated results with E d = 10 eV and E s = 1.6 eV for nitrogen agreed well with experimental values of the sputtering yield, the depth profile and the retained fluence of nitrogen obtained by Rutherford backscattering spectrometry and resonant nuclear reaction analysis for 50 keV nitrogen implantation at fluences of 6 × 10 16 to 2 × 10 18 ions cm −2. The thickness of the nitrogen-implanted layer saturated at high fluence and it was nearly equal to the sum of the mean projected range and the straggling value for all energies from 10 keV to 1 MeV.