Distribution of nitrogen implanted in iron as a function of fluence

Abstract

The effect of the fluence on the evolution of the distributions of 40 keV nitrogen-ions implanted into iron has been investigated. The distributions were determined by using the ¹⁵N(p, αγ)¹²C nuclear resonance reaction at 429 keV. The study shows a considerable reduction in the saturation areal density of ions retained, in relation to the simplest ion collection model. The mean sputtering yield for a 5–10¹⁷ ions-cm⁻² fluence has been determined by 2 MeV-⁴He backscattering. Some experiments of isotopic marking by ¹⁴N and ¹⁵N implantations have brought some interesting features concerning the nitrogen distribution and the mixing. Two simple models were designed in order to justify our experimental results, but only one is presented here. This model is based upon a nitrogen outdiffusion linked to chemical reactions under beam.