SIMS with Very High Spatial Resolution Using Liquid Metal Ion Sources

The practical lateral spatial resolution of scanned ion microprobes has been limited until recently to ≳ 1μm by the relatively low brightness and large source size of duoplasmatron ion sources [1]. During the last decade liquid metal field-ion sources (LMFIS) have been developed with much higher brightness (~106 A/cm2.sr) and small source size (<100nm) [2,3] : it was recognised early on that these sources were potentially very suitable for ion probes with sub-micron resolution [1, 31. SELIGER and coworkers [4] showed that probe diameters of less than 100nm at 55keV were possible using gallium ion.