Combined SIMS-SPM Instrument for High Sensitivity and High Resolution Elemental 3D Analysis - SIMS-SPM

Coordinating Institution: CRP Gabriel Lippmann
Other Partner(s): Ferrovac GmbH , Nanonis - Specs GmbH (CH) , University of Basel (Switzerland)
From: 01/01/2009
To: 31/12/2011
Budget: 600,000.00€
Contact(s): Wirtz Tom

Summary

Thanks to its excellent sensitivity, its high dynamic range and its high mass resolution, SIMS (Secondary Ion Mass Spectrometry) is an extremely powerful analysis technique for surfaces and thin films. Its main fields of application are the semi-conductor industry, metallurgy, glass industry, organic industry and, the more and more often, nanotechnologies, biology and medicine. The obtained 3D resolution of SIMS is however often much worse than what could be expected considering the instrumental performances.

As a matter of fact, the sample surface presents an initial roughness, which leads to an uncertainty on the depth scale. Moreover, this roughness changes during the ion bombardment as the local sputtering yields depend on parameters such as the local angle of incidence of the ion beam, the crystal orientation, …

Complementary in-situ Scanning Probe Microscopy (SPM) mappings of the surface roughness of the sample would allow correcting the SIMS images with respect to the artefacts mentioned above. A careful image overlay procedure would ensure exact alignment of the resulting SPM images with the area analyzed by SIMS. As a consequence, the total eroded depth could be determined as a function of the lateral position within the sputter crater, thus allowing an independent depth scale calibration on each pixel of the imaged area.

Combining the mass spectral data processed this way with the topography information from the SPM images, it would be possible to reconstruct the true spatial distribution of species within the investigated sample volume. This project thus aims at combining SIMS with Scanning Probe Microscopy (SPM). In 2009 the SIMS-SPM prototype instrument has been designed and is currently being assembled. Furthermore a software program was developed for combining the topographical information from AFM with chemical information from SIMS. This software includes a careful image overlay procedure ensuring the exact alignment of the resulting AFM images with the area analysed by SIMS. As a consequence, the total eroded depth could be determined as a function of the lateral position within the sputter crater, thus allowing an independent depth scale calibration on each pixel of the imaged area.

Programme:

ERA-Nets MATERA/MNT

Foreign Funding Agency:

CTI (Switzerland)