Vertical Oxide Semiconductor TFT for High ON Current
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Solution Overview
Problem
Conventional liquid crystal display devices face limitations in reducing channel length and improving ON current due to exposure limitations, which restrict effective mobility and ON current enhancement.
Innovation Solution
A display substrate with a thin film transistor (TFT) channel formed perpendicular to the substrate, utilizing an oxide semiconductor pattern comprising Ga, Zn, In, and Sn, and a manufacturing method that includes forming trenches and insulating layers to accurately control channel length and position the gate electrode for enhanced mobility and ON current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the channel length is reduced to improve ON current, then the exposure limitation prevents further reduction of channel length
Solution Approach 1:
The patent transitions from a planar channel structure to a vertical channel structure by forming the channel in the thickness direction of the substrate. This dimensional change allows the channel length to be controlled by the thickness of the channel layer rather than by lateral exposure dimensions, thereby overcoming the exposure limitation and enabling further reduction of channel length to improve ON current.
Solution Approach 2:
The patent changes the controlling parameter for channel length from lateral dimensions (width/length ratios) to vertical dimension (thickness). By controlling the thickness of the channel layer through deposition processes rather than exposure processes, the patent achieves precise channel length control and overcomes the exposure limitation that previously constrained channel length reduction.
2Productivity
If the channel length is reduced, then the effective mobility needs to be increased to further improve ON current
Solution Approach 1:
The patent employs an oxide semiconductor material (such as IGZO - indium gallium zinc oxide) as the channel layer, which is a composite material with superior electrical properties. This material provides high effective mobility and stable electrical characteristics, enabling further ON current improvement through its inherent material properties rather than solely relying on geometric parameter optimization.
Data Source
AI summary
A display substrate according to the present invention comprises a gate line formed on a substrate, a data line, a thin film transistor connected to the gate line and the data line respectively and pixel electrode connected to the thin film transistor, wherein a channel of the thin film transistor is formed in a direction perpendicular to the substrate and, a layer where the channel is formed includes an oxide semiconductor pattern. ON current of thin film transistor of the display substrate can be increased without loss of aperture ratio.