Overview

Ion Beam Analysis is an enabling technology for thin film scientists and engineers. It is a powerful group of analytical techniques for determining the elemental composition of thin films. We can get accurate (and traceable) analyses, with good spacial resolution both laterally and in depth, and the Surrey IBC is an acknowledged world leader in this field.

IBA techniques have recently become much more powerful, since the self-consistent analysis of photon emission (PIXE) spectra together with particle scattering (RBS, EBS, ERD, NRA) spectra has become available. These new methods, which we have been instrumental in developing, fully exploit the complementary information available from the photon and particle methods: with the depth resolution and traceability of RBS and the mass resolution and sensitivity of PIXE. And all this at the lateral resolution given by our microbeam, and soon also our nanobeam.

We have analysed a very wide range of materials, from various electronics samples through timbers from the Cutty Sark and paint on a suspected Leonardo da Vinci painting to the metal content of proteins. If you have a trace element problem, or you want to know what your thin film really is, then come to us!

Facilities:

We have a 2MV Tandetron  from High Voltage Engineering Europe installed in Summer 2001 and commissioned Easter 2002 with two beam lines :  a microbeam line commissioned Summer 2002 and a millibeam line commissioned Autumn 2002.  

The microbeam line is equipped with a magnetic quadrupole triplet lens and magentic scanner unit from Oxford Microbeams Ltd capable of focussing the beam to 1micron diameter and scanning over 2mm square.

The millibeam is equipped with a 6 movement goniometer from Arun Microelectronics Ltd and a sample exchange mechanism through an airlock.  The sample holder is 150mm * 100mm.  The goniometer can turn the sample to glancing beam incidence angles and is suitable for high resolution depth profiling and depth profiling of H (and D) using  4He ERD.

• RBS, EBS, ERD, PIXE, selected NRA with up to 2.5 MeV H, 6MeV 4He and 1.4MeV 3He beams.
• Multi-axis channelling with a UHV 6 movement goniometer (RBS/EBS/ERD).
• Microbeam analysis of laterally inhomogeneous samples (PIXE/RBS/NRA).
• Cold stage analysis of delicate samples using microbeam (RBS/EBS, PIXE, NRA)

Data Analysis:  

The unique Surrey " IBA DataFurnace " software (based on a "simulated annealing" algorithm) enables automatic, self-consistent analysis of multiple RBS, EBS and ERD spectra, allowing rapid and economic quantitative analysis of large batches of complex samples.  Error bars on the depth profiles obtained (see below) are derived using Bayesian inference techniques.  These new data reduction techniques have revolutionised ion beam analysis, making it widely available as an industrial characterisation tool.

We offer an analysis service to industry

Materials analysed by IBA:

Ion beam analysis can be used for many different types of thin film samples,  and here are just a few that we have looked at:

Semiconductor Materials

• Accurate determination of ion dose for implanted samples (RBS).
• Accurate depth profiles for diffused heterostructures (RBS).
• Silicidation kinetics (RBS).
• Annealing kinetics in implanted single crystals from damage profiles (RBS-c).
• Light element analysis (H, C, N, O) of amorphous group IV alloys (RBS/ERD).

• Tribological coatings such as TaC (RBS/EBS).
• Optical multilayers (RBS).

• Profiles of Cl at sub-0.5% in cement (PIXE).
• Characterisation of cement type (PIXE).
• Major, minor and trace element analysis of biological materials (PIXE/RBS).
• Interdiffusion of deuterium-labelled and unlabelled polymers (NRA).

Glossary

• RBS - Rutherford Backscattering for depth profiles of complex thin films (up to a few microns thick and down to a few nm depth resolution).
• EBS - Elastic (i.e. non-Rutherford) backscattering (for better C, N, O analysis).
• ERD - Elastic Recoil Detection (used for H analysis).
• PIXE- Particle (usually proton) Induced X-ray Emission (ppm sensitivities).
• NRA - Nuclear Reaction Analysis (isotope specific).