Auger analysis of plasma treated ultrananocrystalline diamond films

Ultrananocrystalline diamond films have attracted great research interest due to their properties approaching those of diamond. In a cycle of works we study the treatment of such layers in oxygen or ammonia plasma. In the first case the treatment time is tracked; and in the second one we monitor the influence of different additions (fluorophore, maleimide, etc.). In the current work the accent falls on the Auger analysis (AES). With a view to the electronic spectroscopies, this is a research of the partial monoatomic overlayer. Since there is more than one adsorbate, it suggests a solution for the general case of n adsorbed elements giving their fractional monolayer coverage. This solution is an approximation for energy above 150 eV, however, it is exact in respect of the magnitude of the fractional monolayer coverage. The research showed a significant surface modification of the ultrananocrystalline diamond films in oxygen and ammonia plasma. The fractional monolayer coverage is in the range of dozens of percentages. The monolayer coverage model gives values for the adsorbed quantities about 1.9 times higher as compared to the values, obtained by the homogeneous one. The comparison between AES and X-ray photoelectron spectroscopy (XPS) results for the coverages, shows qualitative similarity. The usage of realistic model of the adsorbed layer is crucial for the quantification.