DEPTH PROFILOMETRY OF SPUTTERED NI IONS IMPLANTED IN TI USING PULSED ARGON AND NITROGEN PLASMAS

A brief description is given of a prototype 4 pi ion implanter (4 pi I I) which uses a compact electron cyclotron resonance (ECR) source for plasma production. In 4 pi II pulsed Ar and N-2 plasmas were used to s putter and ionize Ni from a target biased to -2 kV. Ions are extracted through a grounded grid, which surrounds the sample under implantatio n, and are accelerated toward the samples biased to -30 kV. X-ray phot oelectron spectroscopy was used to measure the depth profile and atomi c concentration of the species constituting the first 50 nm of the Ti sample surface. The measured Ni profile can be modelled by considering the implantation of 30 keV ions together with deposition and ion mixi ng. The difference between the profile shapes for samples processed in Ar and N-2 plasmas can be attributed to the difference in the charact eristics of the processing plasma. Traces of Cr and Fe impurities were also detected on the surface of the sample implanted in the Ar plasma . These impurities most likely originated from the chamber wall or the stainless steel grid used for controlling potential distribution in t he 4 pi ion implanter. (C) 1997 Elsevier Science S.A.