A direct study was made of the elemental depth profiles of Au/Ti and Au/Pt/Ti multiple-layers, which were candidates as ohmic materials for a p-type diamond substrate, grown on diamond (001) surfaces at room temperature and 550C using Rutherford back-scattering method. Significant interlayer diffusion between Au and Ti was observed for the samples without a sandwiched Pt layer, resulting in diffusion of some Ti atoms to the surface. On the other hand, the trilayer structure of Au/Pt/Ti forms a thermally stable electrode up to 1000C. It was also found that the interfacial TiCx layer grown at 550C was thicker than that deposited at room temperature followed by post-deposition annealing at 550C. The effective thickness of the Pt layer was estimated to be more than 20nm to prevent Ti segregation to the surface.

Interdiffusion Analysis of Au/Ti and Au/Pt/Ti Electrode Structures Grown on Diamond (001) Surface by Rutherford Backscattering Spectroscopy. Y.Hoshino, Y.Saito, J.Nakata: Japanese Journal of Applied Physics, 2010, 49[10], 101302