Atomic layer deposition for rutile structure TiO2 thin films using a SnO2 seed layer and low temperature heat treatment

Abstract

We study the rutile-TiO2 film deposition with a high-k value using a SnO2 seed layer and a low temperature heat treatment. Generally, heat treatment over 600 degrees C is required to obtain the rutile-TiO2 film. However, By using a SnO2 seed layer, we obtained rutile-TiO2 films with heat treatments as low as 400 degrees C. The XPS analysis confirms that the SnO2 and TiO2 film were deposited. The XRD analysis showed that a heat treatment at 400 degrees C after depositing the SnO2 and TiO2 films was effective in obtaining the rutile-TiO2 film when the SnO2 film was thicker than 10 nm. The TEM/EDX analysis show that no diffusion in the thin film between TiO2 and SnO2. The dielectric constant of the TiO2 film deposited on the SnO2 film (20 nm) was 67, which was more than twice as high as anatase TiO2 dielectric constant (Anatase TiO2 dielectric constant : 15-40). The current density was 10(-4 )A cm(-2) at 0.7 V and this value confirmed that the leakage current was not affected by the SnO2 seed layer.