Effect of Advanced Plasma Source bias voltage on properties of HfO2 films prepared by plasma ion assisted electron evaporation from metal hafnium

• HfO2 films are evaporated with different Advanced Plasma Source (APS) bias voltages.
• Properties of HfO2 films are sensitive to APS bias voltage.
• With a bias voltage of 100 V, HfO2 coatings without any stress can be achieved.
• Higher 1064 nm laser induced damage threshold is achieved at a bias voltage of 100 V.

HfO2 films, using metal hafnium as starting material, are deposited by plasma-ion assisted electron evaporation with different Advanced Plasma Source (APS) bias voltages. The refractive index and extinction coefficient are calculated, the chemical state and composition, as well as the stress and aging behavior is investigated. Laser induced damage threshold (LIDT) and damage mechanism are also evaluated and discussed. Optical, structural, mechanical and laser induced damage properties of HfO2 films are found to be sensitive to APS bias voltage. The film stress can be tuned by varying the APS bias voltage. Damage morphologies indicate the LIDT of the HfO2 films at 1064 nm and 532 nm are dominated by the nodular-defect density in coatings, while the 355 nm LIDT is dominated by the film absorption. HfO2 films with higher 1064 nm LIDT than samples evaporated from hafnia are achieved with bias voltage of 100 V.