The stability of thin tellurium and tellurium alloy films for optical data storage: II

Abstract

The chemical and physical degradation and the effects of the substrate and a low surface energy subbing layer on the stability of thin tellurium and tellurium alloy films for optical data storage are reported. Chemically, thin tellurium films degrade mainly through the uniform oxidation of tellurium to TeO 2. In addition, localized degradation occurs at regions where initial defects on the substrate are present. Thin tellurium and tellurium alloy films can also degrade physically through crystal growth for an initially polycrystalline film and phase transformation for an initially amorphous film. While no significant difference in the uniform degradation rate is observed between films deposited onto poly(methyl methacrylate) (PMMA) and those deposited onto glass substrates, more localized degradation is detected for the films deposited onto PMMA substrates because of the higher initial defects of the substrate. The presence of a low surface energy subbing layer tends to degrade both the chemical and physical stability of these films. The degradation in the chemical stability is attributed to the change in the microstructure or thickness of the film due to the presence of the low surface energy subbing layer.