Pulsed Laser Deposition and Analysis for Structural and Electrical Properties of HfO2–TiO2 Composite Films

We have developed growth processes for HfO2–TiO2 composite films using a pulsed-laser-deposition (PLD) method and investigated the film structure which is characteristic to the growth sequences. Structural and electrical properties of the films sensitively depend on the growth conditions. It is observed that crystallization of the film is suppressed by increasing the TiO2 content. In the case that HfO2/TiO2 composition ratio is set to be 50/50, the film is completely in the amorphous phase and, after annealing, the film texture consisting of large HfTiO4 crystalline grains is formed. The dielectric constant of HfO2–TiO2 composite films increases with the increase in the TiO2 content in the film when the content is less than 50 at%. A marked change in the leakage property of the film is observed when comparing two films with 10 and 20 at% TiO2. We examine an optimum condition for the growth of HfO2–TiO2 composite film with both high dielectric constant and low leakage current.