Structural modification of tantalum crystal induced by nitrogen ion implantation

Abstract

This paper investigates the effect of nitrogen ion implantation on tantalum surface structure. In this experiment, nitrogen ions which had an energy of 30 keV and doses of 1 × 1017 to 10 × 1017 ions cm-2 were used. X-ray diffraction analysis (XRD) was applied for both the metallic Ta substrate and the study of new structures that have been created through the nitrogen ion implantation. Atomic force microscopy (AFM) was also used to check the roughness variations prior to and also after the implantation phase. The experimental results show the formation of hexagonal tantalum nitride (TaN0.43) in addition to the fact that by increasing the ion dose, the nitrogen atoms occupy more interstitial spaces in the target crystal. The nitride phase also seen for 3 × 1017 and 5 × 1017 ions cm-2, while it disappeared for higher dose of 7 × 1017 and 1 × 1018 ions cm-2. The FWHM of the dominant peak of tantalum nitride suggest the growth of the crystallités size, which is in agreement with the AFM results of the grains.