Nitrogen implantation in iron: Influence of the beam current density and of the chamber residual pressure

Abstract

Abstract Iron samples were implanted at a fluence of 1017 N+ ions.cm−2 with an energy of 50 keV. The beam current density was varied in the range 6–60 μA.cm−2 as well as the quality of the vacuum in the implantation chamber. Implantations were performed at 150°C to favour the carburization process. Carbon and oxygen contaminations were controlled using nuclear backscattering spectrometry (NBS) with α particles of 5.7 MeV and 7.5 MeV respectively or by using Auger electron spectroscopy (AES). The depth profiles of implanted nitrogen were determined by the 15N(p,αγ) nuclear reaction or by AES when 15N or 14N ions were implanted respectively. Implantation induced chemical phases were characterized using Mossbauer spectroscopy and electron diffraction. It is shown that at 150°C the beam current density which has an influence on the implantation time as well as the contamination carbon content at the surface play an important role in the migration process of nitrogen. Consequently, the nitrogen depth distribut...