Thin films of magnesium diboride (MgB2), an intermetallic compound, possessing superconductive properties, were analysed by secondary ion mass spectrometry (SIMS). The samples were prepared using a new two-step technique of ion implantation followed by plasma treatment. Two kinds of structures were obtained when boron and magnesium were used as targets. Eighty kiloelectronvolt magnesium ions were implanted into boron samples and 100 keV boron ions into magnesium strips. Plasma treatment was performed using hydrogen and argon 1 mu s plasma pulses of fluence 2-5 J/cm(2). Magnetic moment and electrical conductivity measurements confirmed superconducting properties of the obtained layers. SIMS depth profiling was performed using 5 keVAr(+) ion beam (06-350E Physical Electronics) and quadrupole mass spectrometry (QMA 410 Balzers). Sensitivity factors for boron and magnesium were obtained based on SIMS analyses of bulk reference samples MgB2, B and Mg. Obtained results allow modifying technology parameters of thin film MgB2 synthesis. (c) 2006 Elsevier B.V. All rights reserved.