AVS 53rd International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeM

Paper AS-WeM6
Applications of a Bismuth-Cluster Ion Gun in Organic and Inorganic Surface Analysis

Wednesday, November 15, 2006, 9:40 am, Room 2005

Session: Molecular Ion Sources and Characterization of Biomaterials
Presenter: F. Kollmer, ION-TOF GmbH, Germany
Authors: F. Kollmer, ION-TOF GmbH, Germany
R. Moellers, ION-TOF GmbH, Germany
T. Grehl, ION-TOF GmbH, Germany
D. Rading, ION-TOF GmbH, Germany
E. Niehuis, ION-TOF GmbH, Germany
Correspondent: Click to Email
In recent years primary ion clusters are increasingly applied for the analysis of organic surfaces by TOF-SIMS. Since they increase the secondary ion formation efficiency by orders of magnitude cluster sources are replacing the mono-atomic primary ion sources more and more. As primary ion species a large variety of different clusters as Au@sub n@, Bi@sub n@, C@sub n@, C@sub 60@, SF@sub 5@ ,...are applied. Possible drawbacks of cluster sources are the applicable cluster currents (measurement time) and the achievable performance with respect to lateral resolution and mass resolution. Recent advances in molecular surface analysis were made by the application of cluster liquid metal ion sources (LMIG) operated with Au or Bi. These sources combine the fundamental benefits of cluster ion bombardment with a high brightness source capable to achieve a high performance with respect to lateral resolution and mass resolution. In particular the Bi source shows interesting aspects as a large variety of emitted singly and doubly charged ions, high cluster currents, and the ability to operate at very low emission currents. At low emission currents the energy spread of the emitted species is reduced which improves the achievable lateral resolution. In this contribution we address fundamental capabilities of the Bi cluster source as the composition of the emitted primary ion beam, the energy spread of the ions, the stability of the source and the influence of the emission current on these. We applied Bi cluster ions to organic surfaces for micro area analysis and imaging with high lateral resolution. We also found new interesting applications of Bi clusters for inorganic surface analysis and dual-beam depth-profiling.