Pixel Drive Transistor Doping Layout for Low Off Current
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Solution Overview
Problem
Current display devices face challenges in enhancing the drive capability of drive transistors while reducing off current in pixel circuits for light-emitting elements.
Innovation Solution
A display device with a pixel circuit that includes a transistor structure featuring a semiconductor layer with a first channel region and doped regions of varying impurity concentrations, where a high concentration region is adjacent to a low concentration region, and a capacitance element connected to the gate electrode of the drive transistor, allowing a drive current to flow between these regions during light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional doping structure is used in the transistor, then the manufacturing process is simple, but the drive capability is insufficient and off current cannot be reduced
Solution Approach 1:
The patent applies local quality by creating different doping concentrations in different regions of the semiconductor layer. Specifically, the first doped region has a first doping concentration while the second doped region has a second doping concentration that is lower than the first. This local variation in doping concentration allows the transistor to achieve both improved drive capability and reduced off current without requiring complex external structures, thereby resolving the contradiction between reliability improvement and device complexity.
2Power
If high doping concentration is used to improve drive capability, then drive capability improves, but off current increases
Solution Approach 1:
The patent resolves this contradiction by implementing spatially varying doping concentrations. The first doped region near the channel has a higher doping concentration to enhance drive capability, while the second doped region at a distance from the channel has a lower doping concentration to suppress off current. This local quality differentiation allows simultaneous optimization of both opposing requirements.
Solution Approach 2:
The semiconductor layer is segmented into multiple doped regions with different doping concentrations. The first doped region and second doped region are separated by an undoped or lightly doped region, creating distinct functional zones. This segmentation allows the high-doped region to provide drive capability while the low-doped region controls off current, resolving the trade-off between power and harmful factors.
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 configuration improves the drive capability and reduces off current in the drive transistor, optimizing the performance of the pixel circuit for improved luminance and reliability.
Implementation Method 1
a first doped region and a second doped region disposed at both sides of the first channel region, the first doped region and the second doped region being doped with an impurity, the first doped region adjacent to the first channel region being a high concentration region, the second doped region being a low concentration region adjacent to the first channel region and a high concentration region adjacent to the low concentration region
Data Source
AI summary
A semiconductor layer of a drive transistor includes a first channel region, and a first doped region and a second doped region that are doped with an impurity, the first doped region adjacent to the first channel region is constituted by a high concentration region, and the second doped region is constituted by a low concentration region adjacent to the first channel region and a high concentration region adjacent to the low concentration region, and a drive current flows from the first doped region to the second doped region in a light emission period of a light-emitting element.