Interdiffusion Analysis of Au/Ti and Au/Pt/Ti Electrode Structures Grown on Diamond (001) Surface by Rutherford Backscattering Spectroscopy

We have directly studied the elemental depth profiles of Au/Ti and Au/Pt/Ti multiple-layers, which are candidates as ohmic materials for a p-type diamond substrate, grown on diamond (001) surfaces at room temperature (RT) and 550 degrees C using Rutherford backscattering method. Significant interlayer diffusion between Au and Ti is 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 1000 degrees C. It is also found that the interfacial TiC(x) layer grown at 550 degrees C is thicker than that deposited at RT followed by post-deposition annealing at 550 degrees C. The effective thickness of the Pt layer is estimated to be more than 20nm to prevent Ti segregation to the surface. (C) 2010 The Japan Society of Applied Physics