Metal Oxide Thin Film Transistor UV Stability via Insulating Layer Shielding
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Solution Overview
Problem
Metal oxide thin film transistors are sensitive to ultraviolet light, causing a shift in threshold voltage and resulting in unstable display performance due to the conductive channel's sensitivity and the need for light shielding structures that increase parasitic capacitance and processing costs.
Innovation Solution
The design includes a substrate with a gate, a first insulating layer with through holes, and a conductive channel with source and drain portions disposed on the insulating layer, where the source and drain are insulated from each other, and a light shielding metal layer is added to prevent ultraviolet light reflection into the conductive channel, stabilizing the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light shielding structure is added to protect the conductive channel layer from ultraviolet light, then the threshold voltage stability is improved, but the device complexity and processing cost increase
Solution Approach 1:
The patent combines the light shielding function with the existing insulating layer structure. The first insulating layer is configured to both electrically isolate the conductive channel from the substrate and block ultraviolet light from reaching the conductive channel, thereby eliminating the need for a separate light shielding structure while maintaining threshold voltage stability
Solution Approach 2:
The insulating layer is designed to perform multiple functions simultaneously: electrical insulation and ultraviolet light shielding. By making the insulating layer multi-functional, the patent avoids adding extra structural elements, thus reducing device complexity while ensuring reliable threshold voltage performance
2Reliability
If a light shielding structure is added to protect the conductive channel layer, then the threshold voltage stability is improved, but the manufacturing cost increases
Solution Approach 1:
The light shielding function is integrated into the insulating layer that is already part of the standard transistor structure. This merging approach means no additional manufacturing steps or materials are required beyond what is already needed for electrical insulation, thereby maintaining cost-effectiveness while achieving threshold voltage stability
3Reliability
If the source, drain and light shielding structure are stacked, then the conductive channel is protected, but the parasitic capacitance increases
Solution Approach 1:
The patent extracts the light shielding function from a separate stacked structure and integrates it into the insulating layer. This eliminates the need for additional stacked layers of source, drain, and light shielding structures, thereby reducing parasitic capacitance while still protecting the conductive channel from ultraviolet light through the insulating layer's inherent shielding properties
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 prevents threshold voltage shifts under ultraviolet light irradiation, enhancing stability and display quality by blocking light reflection and reducing parasitic capacitance.
Implementation Method 1
a light shielding metal layer is added to prevent ultraviolet light reflection into the conductive channel
Implementation Method 2
a first insulating layer, disposed on the gate and the substrate, wherein the first insulating layer is provided with a first through hole penetrating the substrate and a second through hole penetrating the substrate
Data Source
AI summary
Disclosed is a metal oxide thin film transistor and a manufacturing method thereof. By disposing a portion of the source and a portion of the drain in the same layer as the first insulating layer, the reflection of the ultraviolet light by the source, the drain and the first insulating layer can be blocked from entering the conductive channel. Therefore, a threshold voltage shift of the metal oxide thin film transistor under irradiation of ultraviolet light to the conductive channel can be prevented, and the threshold voltage stability and display quality are improved.