Novel floating‐type low‐energy ion gun for high‐resolution depth profiling in ultrahigh vacuum

A floating‐type low‐energy ion gun (FLIG) has been developed for high‐resolution depth profiling in ultrahigh vacuum (UHV). This UHV‐FLIG allows Ar + ions of primary energy down to 50 eV to be provided with high current intensity. The developed UHV‐FLIG was sufficiently compact, being ∼30 cm long, to be attached to a commercial surface analytical instrument. The performance of the UHV‐FLIG was measured by attaching it to a scanning Auger electron microprobe (JAMP‐10, Jeol), the base pressure of which in the analysis chamber was ∼1 × 10 −7 Pa. The vacuum condition of ∼5 × 10 −6 Pa was maintained during operation of the UHV‐FLIG without a differential pumping facility. Current density ranged from 41 to 138 µA cm −2 for Ar + ions of primary energy 100–500 eV at the working distance of 50 mm. This ensures a sputtering rate of ∼10 nm h −1 with 100 eV Ar + ions for Si, leading to depth profiling of high resolution in practical use. Copyright © 2003 John Wiley & Sons, Ltd.