Array Substrate TFT Channel Geometry for Laser Crystallization Uniformity
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Solution Overview
Problem
The existing excimer laser annealing technology for crystallizing silicon layers in array substrates results in uneven channel performance across transistors due to periodic crystallization changes, leading to differences in brightness between pixels and affecting display uniformity.
Innovation Solution
The design of a thin-film transistor with a channel shape that includes specific zones overlapping with the gate electrode, where the ratio of widths W1/W2 ≤ 3, reduces the difference in crystallization defects caused by the back edge of the laser beam, thereby improving channel performance uniformity across different pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If excimer laser annealing technology is used to crystallize the silicon layer, then the silicon layer can be crystallized to form a polysilicon film, but the laser beam stepping along a certain direction with a fixed step size causes periodic crystallization changes, resulting in uneven channel performance and different brightness between pixels
Solution Approach 1:
The gate electrode is designed with asymmetric structure, dividing the channel into a first channel portion and a second channel portion with different widths. The first gate electrode overlaps with the first channel portion while the second gate electrode overlaps with the second channel portion, creating asymmetric electrical characteristics that compensate for the periodic crystallization variations caused by laser beam stepping, thereby improving channel performance consistency across pixels
Solution Approach 2:
Different regions of the channel are given different widths to address local crystallization quality variations. The first channel portion has a different width than the second channel portion, allowing each region to be optimized for its local crystallization characteristics, thus improving overall channel performance uniformity despite periodic variations from the laser process
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
This design enhances the uniformity of display brightness by minimizing performance differences between transistors, leading to improved display uniformity and increased channel length while maintaining the channel's overall length.
Implementation Method 1
A mainstream technology is an excimer laser annealing technology, in which laser beams are used to scan an amorphous silicon layer so that the amorphous silicon layer is crystallized to form a polysilicon film
Implementation Method 2
the amorphous silicon layer is crystallized to form a polysilicon film
Data Source
AI summary
An array substrate, a display panel, and a display apparatus are provided. The array substrate includes a substrate and a first thin-film transistor located on the substrate. In an embodiment, the first thin-film transistor includes a channel and a gate electrode. In an embodiment, an orthographic projection of the gate electrode on the substrate overlaps with an orthographic projection of the channel on the substrate. In an embodiment, the gate electrode comprises a first zone and a second zone that are arranged in a first direction. In an embodiment, the channel overlapping with the first zone in a direction perpendicular to the substrate has a total width W1 in a second direction perpendicular to the first direction, the channel overlapping with the second zone in a direction perpendicular to the substrate has a total width W2 in the second direction, and W1/W2≤3.