Compositional investigation on CVD diamond films by means of Proton Induced X-ray Emission.

The detection of heavy atomic impurities in CVD diamond films performed by means of Proton Induced X-ray Emission (PIXE) technique is here reported. The proton beam has been generated by a Van Der Graft accelerator at energies ranging between 1 and 3 MeV. We have directed the beam to the sample in order to perform maps of the impurity distributions of atoms having atomic number not lower than silicon. The spot size is about 0.5 mm and the penetration depth for our analysis is of the order of a few tenths of microns, so it is a bulk investigation. On the order hand the sensitivity is approximately 01. ppm, then this technique is a very useful tool for the quality control of the deposition chamber and process. Several diamond samples deposited by different CVD methods have been investigated. The results have been related to the distribution of metals inside the reactors, i.e. to the geometry of the systems.