We were succeeded to prepare SiO₂ thin film from the silazane by low temperature solution process. This process enables to fabricate the SiO₂ thin film with good quality at low temperature below 100 ºC. So it is easily prepared on a flexible plastic sheet with no thermal damage (picture). The organic thin film transistor (OTFT) using the solution processed SiO₂ thin film as a gate insulator was comparable to that using thermally oxidized SiO₂ thin film, indicating that the solution processed SiO₂ thin film was such useful for the gate insulator of OTFT as the thermally oxidized SiO₂ thin film.