Thin film transistor, display substrate, method for fabricating the same and display device

Abstract

The present invention provides a thin film transistor, a display substrate, a method for fabricating the same, and a display device, belonging to the technical field of display. The method for fabricating the thin film transistor includes: forming a light-shielding metal pattern and a source / drain metal layer pattern on a substrate; forming a buffer layer; performing photographic composition on the buffer layer to form a first through hole exposing partially out of the light-shielding metal pattern and a second through hole exposing partially out of the source / drain metal layer pattern; forming a semiconductor layer pattern on the buffer layer, wherein the semiconductor layer pattern includes a source region, a drain region, and an active layer between the source region and the drain region and the source region is connected with the light-shielding metal pattern through the first through hole and the drain region is connected with the source / drain metal layer pattern through the second through hole; forming a gate insulating layer and a gate electrode on the semiconductor layer pattern; and using the gate electrode as a mask film to conductively process the source region and the drain region to form the source electrode and the drain electrode of the thin film transistor. The invention can ensure the good qualification rate of the thin film transistor and the display effect of the display substrate.

Description

technical field [0001] The invention relates to the field of display technology, in particular to a thin film transistor, a display substrate and a manufacturing method thereof, and a display device. Background technique [0002] Because the top-gate oxide TFT (thin film transistor) has low parasitic capacitance and excellent electrical characteristics, it is considered to be the first choice for large-scale and high-resolution AMOLED (active matrix organic light-emitting diode) displays. Technical solutions. Top-gate TFTs are often manufactured using a self-aligned coplanar structure. In a TFT with a top-gate self-aligned coplanar structure, the oxide active layer is located below the source-drain metal layer and the gate metal layer, close to the substrate. The substrate is easily irradiated by external light sources or ambient light, and the light stability of the oxide active layer is poor. Therefore, the top-gate oxide TFT often needs to make metal patterns under the o...

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Problems solved by technology

[0003] Since the prior art needs to use a special patterning process to make a metal pattern for light shielding, the number of patterning processes for the top-gate oxide TFT will be increased, resulting in more patterning processes for the top-gate oxide TFT. The production cost is high; and in the prior art, in order to improve the electrical characteristics of the top-gate TFT, the metal pattern used for shading is generally electrically connected to the source-drain metal layer, and the via holes connecting the metal pattern and the source-drain metal layer need to be connected simultaneously. Through the interlayer insulation layer and buffer layer, the depth of the via hole is relatively large, which increases the difficulty of the drilling process, and is prone to process defects, such as lap disconnection

At the same time, in TFTs with a top-gate self-aligned coplanar structure, the conductorized oxide active layer is often used as source electrodes, drain electrodes and data lines. Cause serious IR Drop (voltage drop) phenomenon, affecting the display effect

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