Preparation method of thin film transistor substrate, thin film transistor substrate and display device

Abstract

The invention discloses a preparation method of a thin film transistor substrate, the thin film transistor substrate and a display device. The preparation method of the thin film transistor substrate comprises the following steps that stacking an active layer, a gate insulating layer and a gate layer sequentially on a substrate; stacking a first interlayer dielectric layer, a second interlayer dielectric layer and a third interlayer dielectric layer sequentially, wherein the first interlayer dielectric layer and the second interlayer dielectric layer are both made of silicon oxide, and the content of oxygen in the material of the first interlayer dielectric layer is larger than that of oxygen in the material of the second interlayer dielectric layer, the third interlayer dielectric layer is made of silicon nitride or silicon oxynitride; forming a source contact hole and a drain contact hole; forming a source / drain material layer; forming a source electrode and a drain electrode; and removing the third interlayer dielectric layer to obtain the thin film transistor substrate. According to the invention, SD residue can be avoided.

Description

technical field [0001] The present invention relates to the technical field of thin film transistors (TFT), and more particularly, to a method for preparing a thin film transistor substrate, a thin film transistor substrate and a display device. Background technique [0002] refer to figure 1 , in the prior art, a thin film transistor (TFT) substrate includes a substrate 111, a buffer layer 112 formed above the substrate 111, an active layer 120, a gate insulating layer 130 and a gate layer 140 sequentially stacked above the buffer layer 112 , and the interlayer dielectric layer 150 . The interlayer dielectric layer 150 covers the entire surfaces of the gate layer 140, the gate insulating layer 130 and the active layer 120, and a source contact hole (corresponding to the source 161) and a drain contact hole (corresponding to the drain electrode 161) are respectively formed in the interlayer dielectric layer 150. electrode 162), exposing the active layer 120, depositing a s...

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Problems solved by technology

[0003] In the prior art, the interlayer dielectric layer 150 is usually a single-layer silicon oxide layer, which is formed at one time by a CVD process. The disadvantage of the prior art is that the film-forming property of the silicon oxide layer at the corner of the step of the gate 140 is poor, specifically It is manifested as unevenness, uneven texture, and many lattice defects, which lead to poor film formation of the source / drain material layer deposited above it, and there are many lattice defects, so that when the source / drain material layer is etched The drain material (SD) layer is difficult to be etched when forming the source 161 and the drain 162, forming SD residues 200 protruding outward (see image 3 ),like figure 2 and image 3 As shown, SD residue 200 will seriously cause short circuit of the device, reducing device performance and yield

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