Improvement of electrical properties of silicon oxide thin film with ultraviolet and organic gas assisted annealings

In order to form a silicon oxide thin film at a low temperature, we employed the reaction between spin-coated silicone oil and ozone gas at a low temperature of 250 °C. In the formed silicon oxide films, a large number of SiOH bonds were observed. To reduce the amount of impurities such as SiOH bonds, the silicon oxide film underwent ultraviolet (UV) light treatment and alcohol-assisted annealing. The combination of dipping in ethanol and thermal annealing in methanol gas effectively reduced SiOH bonds. It was hypothesized that the SiOH bonds were displaced with SiOCH3 bonds due to the alcohol treatment. After UV treatment and alcohol annealing, the network SiOSi bonds increased, and the cage SiOSi bonds decreased. It was predicted that the cage SiOSi bonds were broken by UV light and the bonds recombined to form the network SiOSi bond. The dielectric property after UV treatment and alcohol annealing was improved owing to the decrease in the cage SiOSi and SiOH bonds.