Effect of N₂O gas for Reactive Sputtering Deposition of (λ/4) HfO₂ / (λ/4) SiO₂ Distributed Bragg Reflector

抄録

This paper demonstrates the effect of N₂O gas on HfO₂ thin film and (λ/4) HfO₂ / (λ/4) SiO₂ distributed Bragg reflector (DBR) during reactive sputter deposition. HfO₂ thin film fabricated with N₂O as reactive gas during sputter deposition improved its surface roughness and crystal structure. A remarkable improvement of optical transmittance in HfO₂ thin film deposited with N₂O gas was also found. An optimum supply of oxygen atoms is considered to give efficient oxidation for hafnium metal during reactive sputter deposition due to the relatively small dissociation energy from N₂O molecules to N₂ molecules and O atom. The transmittance of (λ/4) HfO₂ / (λ/4) SiO₂ DBR value was obtained to be 98 %. This value is close to the optical transmittance of the dielectric multilayer for highly efficient microcavity.