High Depth Resolution SIMS Analysis with Low-energy Grazing O2+ Beams

By the use of a deceleration electrode in the primary beam line of a magnetic sector SIMS instrument, an O2+ primary beam of variable energy and angle has been produced. The SIMS measurements of ultrathin Ge and B layers in Si were performed with low-energy (0.7–2 keV) and grazingly incident (50–75°) O2+ ions. Consequently, ultrahigh depth resolution with characteristic exponential leading and decay lengths of 0.25 and 0.9 nm, respectively, and 1.6 nm full width at half-maximum for a Ge delta layer was obtained. A depth profile analysis without any appreciable loss in depth resolution was achieved down to a depth of 1 μm with a 1 keV 60° O2+ beam. Furthermore, good dynamic range, acceptable detection limit and moderate sputtering rates were achieved in this ultrahigh depth resolution mode.