JPS6435959A - Thin film transistor - Google Patents

Abstract

PURPOSE:To make it possible to reduce the electric charges generated in the interface of the active layer and the gate insulating film and the vicinity thereof even for a low-temperature process by using as the gate oxide film a SiO2 film formed by a deposition method and annealed in an oxygen atmosphere containing halogen atoms. CONSTITUTION:On an insulating substrate 1 of quartz, pyrex or the like, an active layer 5, a gate oxide film 10, a gate electrode 6, a source 2 and a drain 3 are formed, and on these an inter-layer insulating film 7 is stacked. The active layer 5 is a polysilicon thin film or an amorphous silicon, particularly, hydrogenated amorphos silicon thin film, and the gate insulating film is a SiO2 film formed by a deposition method and annealed in an oxygen atmosphere containing halogen atoms. With this, the trap density occurring in the interface of the active layer 5 and the gate insulating film 10 and the vicinity thereof is reduced, the process temperature is low, and the threshold voltage is stable.