The interface diffusion and chemical reaction between a Ti layer and a diamond substrate

Abstract

A Ti layer with a thickness of 250 nm has been successfully deposited on to the surface of diamond substrates using the r.f. magnetron sputtering technique. AES analysis indicates that the Ti layer reacted with the diamond substrate to form TiC species on the interface during the deposition. The interface diffusion and reaction between the Ti layer and the diamond substrate are promoted significantly by an annealing treatment at a temperature range of 200–600°C in a high vacuum. The Auger line shapes of Ti LMM and C KLL confirm the formation of TiC species, which results from the interface diffusion and reaction. The interface diffusion and reaction are intensified significantly with the rising annealing temperature. However, the Ti layer is considerably oxidized by residual oxygen when the annealing temperature is over 500°C. A prolonged annealing time at 400°C can not only promote the interface diffusion and reaction greatly, but can also prevent oxidation of the Ti layer. Annealing at a relatively low temperature for a long time may be a good method with which to intensify the interface diffusion and reaction. The apparent activation energy of interface diffusion and reaction is about 12.3 kJ mol−1.