LTPS TFT Channel Doping Layout for Edge Hump Suppression
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Solution Overview
Problem
The parasitic channel of low temperature polysilicon thin film transistors at the inclination angle of edge regions in display panels is turned on in advance due to a difference in threshold voltage, causing a hump effect.
Innovation Solution
A display panel design with a channel portion divided into middle and edge regions, where the doping concentration in the edge regions is higher than in the middle region, and the doping type and concentration are varied to reduce the threshold voltage difference, preventing the parasitic channel from being turned on prematurely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the channel portion uses uniform doping concentration, then the manufacturing process is simple, but the threshold voltage difference between edge regions and middle region causes parasitic channel to turn on in advance
Solution Approach 1:
The channel portion is divided into edge regions and middle region with different doping concentrations. The edge regions have higher doping concentration than the middle region, creating local quality differences that compensate for the threshold voltage reduction at inclined edges, preventing parasitic channel formation while maintaining manufacturing feasibility through selective doping processes.
2Reliability
If the doping concentration in edge regions is increased, then the threshold voltage difference is reduced and parasitic channel is prevented, but the device complexity increases
Solution Approach 1:
The invention applies different doping concentrations to different spatial regions of the channel portion. Specifically, edge regions are doped with higher concentration than the middle region, creating localized property variations that address the parasitic channel issue without requiring complete redesign of the entire device structure.
3Reliability
If the channel portion is divided into regions with different doping concentrations, then the threshold voltage uniformity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The channel portion is divided into edge regions and middle region with different doping concentrations. The edge regions have higher doping concentration than the middle region, creating local quality differences that compensate for the threshold voltage reduction at inclined edges, preventing parasitic channel formation while maintaining manufacturing feasibility through selective doping processes.
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 threshold voltage difference between edge and middle regions, preventing the parasitic channel from being turned on in advance, thereby improving the hump effect and enhancing display performance.
Implementation Method 1
an active layer disposed on the substrate and including a channel portion and doping portions, where the doping portions are disposed at opposite sides of the channel portion
Data Source
AI summary
The present application provides a display panel and a display device. The display panel comprises a substrate and an active layer; the active layer comprises a channel portion and doped portions; the doped portions are arranged on two opposite sides of the channel portion in a first direction; the channel portion is divided into a middle area and edge areas located on two opposite sides of the middle area in a second direction, and the doping concentration of the channel portion in the edge areas is greater than that in the middle area.