Abstract: A method for manufacturing a thin-film transistor (TFT), an array substrate and a display device are disclosed. The manufacturing method includes: forming a photoresist layer provided with a completely retained region, a partially-retained region and a completely removed region on a metal film by a half-tone mask process; forming a source/drain metal layer by etching the metal film under the cover of the photoresist layer; removing the photoresist layer in the partially-retained region; forming an active layer by patterning the semiconductor film; and removing residual photoresist layer.

Abstract: A thin film transistor (TFT), a manufacturing method thereof, a display substrate and a display device are disclosed. The TFT includes: a gate electrode; a gate insulating layer disposed on the gate electrode; a first active layer disposed on the gate insulating layer; a second active layer disposed on the first active layer, having a length smaller than that of the second active layer; a source electrode disposed on the first active layer, being contacted with a first side of the second active layer; and a drain electrode disposed on the first active layer, being contacted with a second side of the second active layer. Embodiments of the present invention can increase an ON-state current and meanwhile reduce an OFF leakage current in the TFT.