Oxide TFT Gate Insulator Layout Against Channel Shortening
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Solution Overview
Problem
In existing metal oxide thin film transistors, conductive ions used to reduce the block resistance of source and drain regions diffuse into the channel region, shortening it and affecting the threshold voltage and stability of the device.
Innovation Solution
The oxide thin film transistor design includes a first active layer with source and drain doped regions, diffusion regions, and a channel region, where the thickness of the gate insulating layer is varied to shield the channel region laterally and reserve a distance for lateral diffusion of conductive ions, preventing the channel region from being shortened.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If source and drain regions are doped with conductive ions to reduce block resistance, then conductivity of source and drain regions is improved, but conductive ions diffuse into channel region causing shortening of actual channel length
Solution Approach 1:
The channel region is divided into multiple segments with different gate insulating layer thicknesses: a first channel region with thicker gate insulating layer to prevent ion diffusion, and second/third channel regions with thinner gate insulating layers for proper device operation. This segmentation allows the channel to simultaneously protect against ion diffusion while maintaining electrical functionality.
Solution Approach 2:
Different regions of the channel are given different local properties through varying gate insulating layer thicknesses. The first channel region has a thicker gate insulating layer specifically designed to resist ion diffusion, while other channel regions have thinner layers for optimal device performance. This local quality differentiation resolves the contradiction between ion blocking and electrical operation.
2Reliability
If conductive ions are doped into source and drain regions to make them conductive, then block resistance is reduced, but threshold voltage of device is seriously affected
Solution Approach 1:
The channel is segmented into regions with different gate insulating layer thicknesses, creating a barrier in the first channel region that prevents conductive ions from reaching and affecting the threshold voltage, while allowing proper device operation in other regions.
Solution Approach 2:
The gate insulating layer acts as an intermediary barrier between the source/drain regions and the channel region. By making this intermediary layer thicker in the first channel region, it mediates the interaction by blocking ion diffusion while still allowing the device to function properly through the thinner regions.
3Length of moving object
If gate insulating layer thickness is increased to prevent ion diffusion, then channel length is maintained, but device performance may be affected
Solution Approach 1:
Different channel regions have different gate insulating layer thicknesses optimized for their specific functions. The first channel region has a thicker layer for ion diffusion prevention, while second and third channel regions have thinner layers for optimal device performance, achieving both goals simultaneously through local quality differentiation.
Solution Approach 2:
The channel is divided into segments with different gate insulating layer thicknesses, allowing each segment to be optimized for its specific role: ion blocking in the first region and performance optimization in the other regions.
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 prevents the shortening of the channel region, ensures an effective channel length, and stabilizes the threshold voltage, thereby improving the performance and reliability of the oxide thin film transistor.
Implementation Method 1
the thickness of the gate insulating layer is varied to shield the channel region laterally and reserve a distance for lateral diffusion of conductive ions
Implementation Method 2
conductive ions used to reduce the block resistance of source and drain regions diffuse into the channel region
Implementation Method 3
source and drain regions are doped with conductive ions to reduce its block resistance and make them conductive
Implementation Method 4
make them conductive
Data Source
AI summary
The present application discloses an oxide thin film transistor, a display panel, and a preparation method thereof. Each thickness of the first gate insulating layer of the present application corresponding to the first source doped region, the first drain doped region, the first diffusion region, and the second diffusion region is less than a thickness corresponding to the first channel region; and thicknesses of the first gate insulating layer corresponding to the first diffusion region and the second diffusion region are both different from a thickness corresponding to the first source doped region and the first drain doped region. The the first gate insulating layer effectively shields the first channel region laterally.