Thin Film Transistor Spacer Layer for Copper Diffusion Blocking
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Solution Overview
Problem
In large-size OLED and liquid crystal display devices, the use of copper for gate formation and metal oxide for active layers leads to instability due to copper diffusion into the active layer, affecting the switching characteristics of thin film transistors.
Innovation Solution
A spacer layer with stronger blocking capability than the gate insulation layer is introduced between the gate and the active layer to prevent material diffusion, ensuring stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used for gate formation and metal oxide for active layer, then low resistance and high resolution are achieved, but copper diffuses into the active layer causing instability
Solution Approach 1:
A spacer layer is introduced as an intermediary component between the gate and the active layer. This spacer layer acts as a diffusion barrier that prevents copper atoms from migrating from the gate into the active layer, while still allowing the device to function properly. The spacer layer is positioned adjacent to the gate and overlaps with the active layer, creating a protective interface that blocks harmful copper diffusion without interfering with the electrical operation of the transistor.
2Object-affected harmful factors
If gate insulation layer is used to prevent copper diffusion, then some protection is provided, but the blocking capability is insufficient at high temperatures
Solution Approach 1:
The solution employs a composite structure consisting of multiple layers with different functional properties. The gate insulation layer (such as silicon nitride or silicon oxide) is combined with a spacer layer made of materials having superior copper diffusion blocking capabilities. This composite barrier structure leverages the complementary strengths of different materials to provide robust protection against copper diffusion even under high-temperature processing conditions during film deposition and annealing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The spacer layer effectively prevents copper or aluminum ions from diffusing into the active layer, stabilizing the thin film transistor and array substrate performance.
Implementation Method 1
a blocking capability of the spacer layer with respect to diffusion of a material forming the gate is stronger than a blocking capability of the insulation layer with respect to the diffusion of the material forming the gate
Data Source
AI summary
The present invention provides a thin film transistor and a method of fabricating the thin film transistor, an array substrate and a method of fabricating the array substrate, and a display device. The thin film transistor includes a substrate and a gate, an insulation layer, an active layer, a source and a drain which are provided on the substrate. A spacer layer is also provided between the gate and the active layer, and the spacer layer overlaps at least with one of the gate and the active layer having a smaller area in an orthographic projection direction. The spacer layer can effectively prevent material forming the gate from being diffused into the active layer, thereby ensuring stability of performance of the thin film transistor. In the array substrate utilizing the thin film transistor, the spacer layer further extends to a region corresponding to a gate line.