Ion Beam Deposition (Veeco NEXUS)
This tool is designed for high quality, precise, reproducible deposition of dielectric films for optical quality films. Metallic material is ion bombarded from a target material and a reactive ion beam of oxygen and/or nitrogen is aimed at the surface, creating a metal-oxide or nitride on the sample. The system is fully computer controlled to facilitate multi-layer stack recipes for high reflectivity or low reflectivity coatings. The system is load locked and can handle wafers up to 6” in diameter as well as small pieces. Sample rotation and angling is used to facilitate material quality and allows for sidewall coverage on non-planar surfaces. Uniformity is better than 1.5% over 6" wafers and reproducibility is expected to be within one percent (with pre-dep calibration). The high-energy sputter deposition produces denser films than other techniques, improving optical damage threshold (and thus coating lifetime). This also causes the refractive indices to be slightly higher than comparable stoichiometric films deposited by other techniques.
Four metallic targets can be installed. Currently available targets are Ta, Si, Al, Ti & ITO (producing Oxides & Nitrides of each). Ta & Si are always available, the others are rotated out as users need.
The most common films for High-/Anti-Reflection (HR/AR) coatings are SiO2 & Ta2O5, both of which are extremely stable w/r/to refractive index. Users typically calibrate their dep. rates prior to critical deps. & multi-layer coatings.
- Xenon target bombardment
- Nitrogen and/or Oxygen deposition assist source for metal oxides/nitrides
- Ta and Si targets (Al and Ti coming soon)
- Pieces up to 6” wafers accepted
- Full programmable control through GUI for multi-layer optical coatings
- Ta2O5 (1.33 A/s rate) and SiO2 (0.85A/s)characterized, standard recipes
- Base Pressure ~ 3e-8 Torr
- High quality, high reflectivity (>99.5%) mirrors demonstrated in blue wavelengths