Nano blisters in multilayer Mo/Si coatings due to bombardment of hydrogen ions

Blistering is one of the major failures for multilayer coatings used in optical systems. By extending the blister mechanics theory of pockets of energy concentration, the nano blisters are studied on the surface of multilayer Mo/Si coatings subject to hydrogen ions bombardment. A mechanical model is developed to determine the mode I and II fracture toughness G_Ic and G_IIc from experimental test data. By using the predicted values G_Ic and G_IIc, the predicted trend lines between the blister radius and height agree very well with the test data.