Ion sputtering of microparticles in SIMS depth profile analysis

The microparticle analysis method, based on the application of a sample rot ation technique in secondary ion mass spectrometry (SIMS) depth profile ana lysis is described. Sample rotation experiments, i.e. ion sputtering with t he application of variable azimuth incidence angle of the primary beam, wer e performed in order to reduce a shadowing effect in the rough surface sput tering. A more uniform erosion process than in the case of standard station ary sample bombardment has been observed. The rotation technique yields a g reater bombarded surface of the individual microparticles than that observe d using the beam with a constant azimuth incidence angle. Surface recession induced by ion erosion of the spherical particle was mode lled using the ANSYS and SRIM codes under the same conditions as those of t he experimental bombardment. The results of the ion-eroded surface are show n in the case of stationary and rotating samples. Ion sputtering of micropa rticles was performed with 150 nA, 4 keV Ar+ ion beam in the SIMS spectrome ter equipped with the 16 mm QMA-410 Balzers quadrupole and the precision sa mple rotation manipulator. Special sample preparation methods were performe d in order to obtain a mini target. Indium matrix with the attached micropa rticles of a known "core-shell" structure was shaped to a 0.6-0.2 mm diamet er substrate. (C) 2001 Elsevier Science Ltd. All rights reserved.