TFT Array Substrate Segmented Active Layer for Leakage Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thin-film transistor (TFT) array substrates face issues with photo-generated leakage current due to the exposure of semiconductor layers, which affects the quality of displayed images, particularly in the five-mask process where the semiconductor layer forms a loop around the source/drain electrode and becomes part of the photo-generated current path, and in the four-mask process where the semiconductor layer is exposed under the metal pattern.
Innovation Solution
The TFT array substrate is designed with an active layer distributed in multi-sections in the peripheral regions, including a doped layer between the active layer and the source/drain electrode, and a metal wire in the same layer as the source/drain electrode, with a light-shielding layer to prevent light irradiation and reduce the formation of a continuous path for photo-generated carriers, thereby alleviating the leakage current issue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the semiconductor layer is formed with a large pattern to ensure alignment yield, then the alignment between source/drain electrode and semiconductor layer is improved, but the exposed semiconductor layer forms a continuous path for photo-generated current, worsening the leakage current problem
Solution Approach 1:
The semiconductor layer in the peripheral region is divided into multiple sections separated by gaps, transforming a continuous structure into a segmented one. This segmentation interrupts the photo-generated current path while preserving the necessary alignment yield from the original large pattern design.
Solution Approach 2:
The semiconductor layer is designed with different structures in different regions: a continuous large pattern in the central region for alignment, and a segmented structure in the peripheral region to block photo-generated current. This local differentiation allows each region to serve its specific function optimally.
2Reliability
If the active layer area is increased to improve device performance, then the electrical performance of TFT is improved, but the area exposed to light increases, worsening the photo-generated leakage current
Solution Approach 1:
The active layer is segmented in the peripheral region to reduce the continuous area exposed to light, thereby reducing photo-generated carriers while maintaining sufficient active layer area in the central region for good electrical performance.
Solution Approach 2:
A doped layer is introduced as an intermediary between the active layer and source/drain electrode. This doped layer acts as a mediator to reduce the formation of photo-generated carriers in the peripheral region while allowing the active layer to maintain its functional area.
3Reliability
If the semiconductor layer forms a loop around the source/drain electrode to ensure complete coverage, then the electrical connection is improved, but the loop structure creates a continuous path for photo-generated current, worsening leakage current
Solution Approach 1:
The loop structure of the semiconductor layer is segmented by introducing gaps, transforming it from a continuous closed loop into a series of disconnected segments. This maintains electrical connection functionality while interrupting the photo-generated current path.
Solution Approach 2:
The harmful continuous loop structure is extracted and replaced with a segmented structure in the peripheral region, removing the photo-generated current path while preserving the essential electrical connection function through the remaining active layer areas.
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 effectively reduces the area of the active layer exposed to light, minimizing the generation of photo-generated carriers and preventing the formation of continuous leakage current paths, thereby improving the image quality by reducing the transmission efficiency of photo-generated carriers.
Implementation Method 1
a light-shielding layer to prevent light irradiation and reduce the formation of a continuous path for photo-generated carriers
Implementation Method 2
Active layers in TFTs generate photo-generated carriers after being irradiated with light, which causes crosstalk and afterimages
Data Source
AI summary
The present application discloses a thin-film transistor (TFT) array substrate and a display panel. The TFT array substrate includes an active layer and a source/drain electrode disposed on the active layer. The active layer includes an electrode coverage region, a channel region, and a first peripheral region disposed around the electrode coverage region and the channel region. The active layer located in the first peripheral region is distributed in multi-sections.