Hydrogen-induced buckling of gold films

In this work, 100 nm gold films with -30 ± 6 MPa residual compressive stress grown by the Volmer-Weber mechanism are exposed to low-flux, low-temperature hydrogen plasma. The films, which were free of any type of blisters prior to plasma treatment, exhibited plenty of buckling zones localized inside circular boundaries after the treatment. This is attributed to compressive stress exerted by the over-pressurized hydrogen gas at the trap zones in the film and at the coating interface. The geometrical parameters of the circular buckling zones indicate a compressive stress of -1.2 ± 0.3 GPa. The findings reveal a serious concern for technological applications involving hydrogen plasma treatment of samples containing thin gold films, but from an optimistic perspective, suggest an efficient cleavage technique for such films. Several methods including reducing the ion impact energy, increasing the sample temperature and changing the substrate material are investigated to suppress hydrogen-induced buckling. Among these, reducing the impact energy of the ions appeared to be the only effective method.