Effects of thermal expansion coefficient mismatch on structure and electrical properties of TiO₂ film deposited on Si substrate

Effects of thermal expansion coefficient (CTE) mismatch on structure and electrical properties of TiO₂ film deposited on Si substrate by ion beam assistant electron beam evaporation have been investigated. Because of a high CTE mismatch between TiO₂ film and Si substrate, microcracks appeared in the TiO₂ film deposited directly on Si substrate after the as-deposited film was annealed at 600°C. In order to decrease the CTE mismatch, TiO₂ film was deposited on Si substrate which was covered by a ZrO₂ thin layer. As a result, crack-free TiO₂ film after annealed at the same temperature was obtained. Meanwhile, corresponding to the crack-free structure, the TiO₂ thin film has more stable dielectric properties and excellent I-V characteristics.