Thin-Film Transistor Layout With Induced Conductorized Channel Edges
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Solution Overview
Problem
Existing thin film transistors (TFTs) face challenges such as damage to the semiconductor layer during manufacturing, limited current driving ability, and high manufacturing costs due to the need for crystallization and high processing temperatures, which affects their performance and uniformity in large area displays.
Innovation Solution
A TFT structure is proposed with a main light shield layer and induced conductorized portions that reduce the resistance of the active layer through a gate field, minimizing channel length and eliminating the need for separate conductorization processing, thereby preventing semiconductor layer damage and improving electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide semiconductor is used as active layer to achieve high mobility and low processing temperature, then electrical properties are improved, but separate conductorization processing is required which increases manufacturing complexity
Solution Approach 1:
The patent merges the conductorization function into the gate insulator layer by forming a conductorized portion within the gate insulator that directly contacts the source electrode and extends to the channel area. This eliminates the need for separate conductorization processing of the oxide semiconductor layer while maintaining electrical connectivity and reducing manufacturing steps.
Solution Approach 2:
The gate insulator layer serves as an intermediary structure that performs dual functions: electrical insulation between gate and source/drain, and providing a conductorized portion for electrical connection. This mediator approach allows the oxide semiconductor to maintain its intrinsic properties while achieving necessary conductorization through the gate insulator's conductorized region.
2Ease of manufacture
If gate insulator layer is etched to form connecting portions, then electrical connection is achieved, but semiconductor layer may be removed or damaged
Solution Approach 1:
The gate insulator layer is segmented into different functional regions: a gate insulator portion for insulation and a conductorized portion for electrical connection. This segmentation allows the conductorized portion to be selectively formed and contacted by the source electrode without requiring etching that would expose and damage the underlying semiconductor layer.
Solution Approach 2:
The conductorized portion is formed within the gate insulator layer before final electrode formation. This preliminary action ensures that the conductorized region is already in place to receive the source electrode contact, eliminating the need for subsequent etching operations that could damage the semiconductor layer.
3Reliability
If polycrystalline Si is used as active layer to improve current driving ability, then mobility is improved, but manufacturing cost increases due to crystallization process
Solution Approach 1:
The patent changes the material parameter from polycrystalline Si to oxide semiconductor, which inherently provides high mobility without requiring high-temperature crystallization processes. This parameter change maintains current driving ability while eliminating the costly and complex crystallization manufacturing steps.
4Ease of manufacture
If amorphous Si is used as active layer to reduce manufacturing cost, then production cost is reduced, but mobility and current driving ability are insufficient
Solution Approach 1:
The patent changes the material parameter from amorphous Si to oxide semiconductor, which provides inherently higher mobility and better current driving ability while maintaining compatibility with low-temperature, cost-effective manufacturing processes. This parameter change resolves the trade-off between cost and performance.
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 structure enhances the TFT's electrical properties, including current characteristics and mobility, while reducing the risk of semiconductor layer damage and enabling low-power operation, thus addressing the limitations of existing TFT technologies.
Implementation Method 1
induced conductorized portions that reduce the resistance of the active layer through a gate field
Data Source
AI summary
Provided are a thin film transistor and a display device. The thin film transistor has a structure in which an active layer has an induced conductorized portion located between a main conductorized portion and a channel area, with the induced conductorized portion overlapping a portion of one side of a light shield layer. The possibility of damage to the active layer is removed or minimized. A short channel is easily realized.