can be found in a one-shot measurement at a constant incident energy. Moreover, this technique offers an opportunity to study the density profiles of hydrogen, carbon and oxygen in various materials, as well as the absolute hydrogen, carbon and oxygen content. Combination of techniques is required in order to study the composition of thin films. Ion beam techniques – RBS and elastic recoil detection analysis combination has proved to be an attractive way to study the elemental composition of the samples as well as the depth profiles of the thin films. ERDA technique is capable of separating masses and energies of scattered incident ions and the recoiled target atoms. It is especially useful to profile light elements such as H, B, C, N, and O in the presence of heavier material background. Thus it has proved to be a useful technique in studying the composition of the thin films. The dependence of the hydrogen density profile on the features of processing and maintenance, and the effect of injected hydrogen on the dielectric properties of ditantalum pentoxide can also be studied. Synonyms and acronyms ERD = Elastic Recoil Detection ERDA = Elastic Recoil Detection Analysis FRS = Forward Recoil Spectrometry FReS = Forward Recoil Spectrometry HFS = Hydrogen Forward Scattering References Materials science