Characteristics of ZnS-SiO_2 Film Used as Phase-change Optical Disk Dielectric Layer

The characteristics of ZnS-SiO2 dielectric film were studied by using AFM, XRD, TEM, UV/Vis/NIR spectrometer, and spectroscopic ellipsometer methods. It was indicated that the as-deposited ZnS-SiO2 film is amorphous and has Straski-Krastanov type growth characteristic. The surface of the ZnS-SiO2 film is very smooth. The grain size of the ZnS-SiO2 film is very small, around 2-10nm. The transmissivity of the ZnS-SiO2 film is large and the extinction coefficient is very small, which are beneficial to reduce the loss of laser power. The refractive index of the ZnS-SiO2 film is large and the recording layer can be protected very well.