SATURATED THICKNESS OF NITRIDE LAYERS FORMED BY HIGH FLUENCE NITROGENIMPLANTATION INTO METALS

The thickness of the nitride layer formed by a high fluence nitrogen i mplantation to a metal surface is limited mainly because of the sputte ring effects and the migration of the implanted nitrogen towards the s urface. We have investigated nitrogen depth profiles implanted to seve ral kinds of metals theoretically by Monte Carlo simulation using the dynamic-SASAMAL code and experimentally by RES and NRA using the N-15( p,alpha gamma)C-12 reaction. In this paper, the saturation fluence and the saturated nitride thickness were calculated for 1-200 keV nitroge n implantations into several kinds of metals (Al, Ti, Fe, Zr, and Hf). In order to find the method to overcome the limited thickness and the severe radiation damage problem at the high fluence implantations nec essary for the saturation, the nitrogen depth profiles for an energy s canning implantation with a uniform and a non-uniform energy distribut ion was calculated and compared with those of mono-energetic implantat ions.