Stress reduction in ion beam sputtered mixed oxide films

Area of Science:

• Materials Science
• Thin Film Deposition
• Optical Coatings

Background:

• Ion beam sputtering often results in high compressive stress in thin films.
• This intrinsic stress can negatively impact film performance and durability.
• Reducing stress is crucial for applications requiring high-quality thin films.

Purpose of the Study:

• To investigate the reduction of compressive stress in thin films by cosputtering.
• To explore the relationship between composition and properties in zirconia-silica mixtures.
• To determine the effect of silica addition on zirconia film stress.

Main Methods:

• Thin films of zirconia (ZrO(2)) and silica (SiO(2)) mixtures were prepared using ion beam sputtering.
• A range of compositions were created to study the effect of mixing.
• Refractive index and stress levels were measured for the deposited films.

Main Results:

• The refractive index of the zirconia-silica films exhibited an almost linear dependence on composition.
• Significant reduction in the high compressive stress, typically observed in pure zirconia films, was achieved by adding silica.
• The addition of silica effectively mitigated the intrinsic stress of the films.

Conclusions:

• Cosputtering zirconia and silica is an effective method for reducing compressive stress in ion beam sputtered thin films.
• The composition-tunable refractive index makes these mixtures suitable for optical coating applications.
• Silica addition is a viable strategy to manage and reduce stress in zirconia-based thin films.