An ion beam assisted deposition (IBAD) technique was employed to prepare Ti/Ni intermediate layers. These intermediate layers were between the magnetron sputtered AuSn film and chemical vapor deposited diamond (CVDD) substrate. IBAD was shown to be very effective in the development of a reliable metallization system for CVDD. The LEAD method increased the interface adhesion between the Ti/Ni layers and CVDD due to the formation of TiC at the diamond-metal interface. The solid state reaction product of such a CVDD/Ti/Ni/AuSn system annealed at 300 degrees C was investigated by Rutherford backscattering spectrometry. The results showed the interaction between the metals in both AuSn and Ni layers of the CVDD/Ti/Ni/AuSn sample during the post-deposition annealing.