Film transistor and manufacturing method thereof and array substrate

Abstract

The embodiments of the invention provide a film transistor and a manufacturing method thereof and an array substrate, which relate to the display technology field and are able to avoid the damage caused by etching solution to the active layer of an oxide in the formation of a source electrode and a drain electrode, which further influences the characteristics and the reliable stability of the film transistor. The film transistor manufacturing method comprises of forming the active layer of an oxide, a source electrode and a drain electrode on a substrate with both the source electrode and the drain electrode comprising a first transparent conductive layer. The first transparent conductive layer covers the active layer of the oxide; the source electrode comprises a first metal layer located on the first transparent conductive layer and away from one side of the substrate and a second transparent conductive layer. The second transparent conductive layer covers the first metal layer. The drain electrode comprises a second metal layer located on the first transparent conductive layer and away from one side of the substrate and a third transparent conductive layer. The third transparent conductive layer covers the second metal layer. The conductivity of the part of the first transparent layer located between the source electrode and the drain electrode is smaller or equal to the conductivity of the active layer of the oxide.

Description

technical field [0001] The invention relates to the field of display technology, in particular to a thin film transistor, a preparation method thereof, and an array substrate. Background technique [0002] Thin Film Transistor (TFT for short) can be classified into Back Channel Etch (BCE for short) type and Etch Stop Layer (ESL for short) type etc. according to different manufacturing processes. Among them, the BCE type TFT is widely used because of its simple process flow. [0003] The difference between the ESL type TFT and the BCE type TFT is that: the oxide active layer and the source and drain of the ESL type TFT also include an etching stopper layer. In the preparation process of ESL type TFT, due to the existence of the etching barrier layer, when wet etching is used to etch the source and drain electrodes, the etching solution will not directly contact the oxide active layer. Therefore, the oxide The surface of the active layer will not be damaged by corrosion. Ho...

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Problems solved by technology

However, if figure 1 As shown, in the manufacturing process of the BCE type TFT, when wet etching is used to etch the source electrode 14 and the drain electrode 15, since the etching solution directly contacts the oxide active layer 13, the oxide active layer 13 The part in direct contact with the etchant is damaged by corrosion, for example: the surface of the oxide active layer 13 in direct contact with the etchant is uneven, depleted of oxygen, and polluted by impurity elements, etc., making the direct contact with the etchant A large number of defect states are generated on the surface of the oxide active layer 13, which affects the characteristics and reliability stability of the TFT

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