Methods for fabricating thin film transistor and array substrate, array substrate and display device

Abstract

Methods for fabricating a thin film transistor and an array substrate, an array substrate and a display device are provided, and the fabrication method of a thin film transistor includes: forming a first photoresist pattern on the active layer film, wherein the first photoresist pattern comprises a photoresist area of a first thickness and a photoresist area in a second thickness; etching the active layer film by using the first photoresist pattern as a mask to form an active layer; ashing the first photoresist pattern to remove the photoresist area of the second thickness and to reduce a thickness of the photoresist area of the first thickness to form the second photoresist pattern. The second photoresist pattern is used as the mask to etch the source-drain electrode thin film. The fabrication method uses the photoresist pattern to prevent the active layer from being impacted by a source-drain etching solution, and can reduce the usage of a specific etching barrier layer and greatly simplify the fabrication process.