Investigation of interface properties of Ti/Ni/Ag thin films on Si substrate

The interface structure and the adhesion of direct current (DC) sputtered Ti/Ni/Ag thin film metallization on n+Si substrate has been investigated. It is shown that beside the chemical preparation of the Si surface prior to sputtering also thermal annealing of sputtered metal structure has strong influence on the adhesion of sputtered layers to the silicon. Energy dispersive X-ray spectroscopy (EDS) analysis were performed on both, the delaminated layers and on the silicon surface to determine the exact delaminating interface, which was found to be between Si and Ti layer. Auger electron spectroscopy (AES) profile revealed no traces of contamination at Ti–Si interface. Measured high tensile residual stress, particularly in sputtered Ni layer (1.4–2 GPa) is found to reduce the metal stack adhesion.