Oxygen-ion-assisted deposition of thin gold films

Thin gold films have been deposited on glass and silicon substrates using ion-assisted deposition techniques. The adhesion of the films to the substrates is assessed by a scratch test. Deposition assisted by 100 eV-1 keV oxygen ions yields highly adhesive films that can only be removed by damaging the substrate. Argon and hydrogen ions produce films with relatively poor adhesion. The results show that the reflectance of oxygen-assisted films is reduced by trapping of the oxygen in the gold but no bulk chemical or structural changes are detected. It is proposed that a thin stable layer of gold oxide is formed during film growth and diffuses into the substrate, providing a strong bond for subsequent film deposition. Highly adhesive films with bulk optical properties are deposited on glass and silicon using oxygen-ion assistance only to the point of continuous film formation.