On the optimization of the PIXE technique for thickness uniformity control of ultra-thin chromium layers deposited onto large surface quartz substrate

Chromium is a good candidate for obtaining conductive ultra-thin layers on insulator substrates such as quartz. The resistivity of such layers is highly related to the quality of the deposited chromium film. In order to optimize the deposition process, there is a need for rapid and accurate monitoring of such films (film thickness, thickness uniformity over a big surface, etc.). In this paper, we demonstrate the ability of the LE-PIXE technique, using proton energies <1 MeV, for the monitoring of the thickness and the thickness uniformity of ultra-thin (0.5 nm < t < 20 nm) chromium layers deposited onto quartz substrates. The acquisition time needed to obtain results with less than 3-4% precision was ∼5 min for the thinnest layers. The validation for the use of the LE-PIXE technique was checked by means of conventional RBS technique