Characterization of tantalum pentoxide films with backscattering spectrometry

The backscattering performance of 2 MeV He⁺ and N⁺ beams was studied using Ta₂O₅ targets as test targets. To allow ready comparison, the scattering geometry, projectile energy, and detection system were kept identical for both beams. Tantalum oxide films with thicknesses of 200 Å to 4000 Å were examined. For thickness determinations, beam straggling was found to be the major limiting factor. For thickness measurements below 1000 Å the N⁺ beam is best suited for larger thicknesses; the He⁺ beam is superior. For stoichiometric determinations both beams provide equally accurated and precise data.