Effect of Al ion implantation on the adhesion of Al films to SiO2 substrates

The effects of Al ion implantation on the adhesion of Al films to SiO2 substrates were investigated. The thickness of the Al films was about 100 nm. 70 keV Al ion implantation was performed with doses of 5×1015 and 5×1016 Al+/cm2. The adhesion was measured by scratch test. It was found that the film adhesion could be improved by more than ten times after implantation. The composition depth profiles of Auger electron spectroscopy showed that implantation results in the formation of Al2O3 at the interface and interface mixing and/or roughening. These factors enhanced the film adhesion. However, tensile stress develops at high implantation dose, which is deleterious to the film adhesion. Transmission electron microscopy and x‐ray diffraction investigation indicates that the grains of the film were refined by implantation.