Display Device Gate Insulating Layer Optimization
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Solution Overview
Problem
High-resolution display devices face challenges in maintaining adequate driving voltages and device characteristics due to the decrease in driving current as the number of pixels increases, leading to reduced range of driving voltages and potential deterioration in device performance.
Innovation Solution
A display device design featuring different gate insulating layers for driving and switching transistors, with the first gate insulating layer made of silicon oxide and the second gate insulating layer comprising layers of silicon oxide and silicon nitride or oxynitride, allowing for controlled device characteristics and improved voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to achieve high resolution, then the display resolution is improved, but the driving current of each pixel decreases
Solution Approach 1:
The patent applies different gate insulating layer structures to different transistor types within the same pixel circuit. The driving transistor uses a first gate insulating layer structure optimized for voltage control, while the switching transistor uses a second gate insulating layer structure optimized for switching performance. This local differentiation allows each transistor to operate optimally despite the reduced driving current in high-resolution displays.
Solution Approach 2:
The patent changes the physical parameters of the gate insulating layers, specifically using different material compositions and thicknesses. The first gate insulating layer has a first thickness designed for the driving transistor, while the second gate insulating layer has a second thickness designed for the switching transistor. These parameter changes enable adequate voltage ranges to be maintained even when driving current decreases due to higher pixel density.
2Measurement precision
If the driving current decreases due to high pixel density, then the display resolution is improved, but the range of driving voltages decreases
Solution Approach 1:
Different gate insulating layer structures are implemented locally for different transistor functions. The driving transistor's gate insulating layer is designed to provide adequate voltage control range, while the switching transistor's gate insulating layer is designed for effective switching at lower voltages. This localized optimization maintains voltage adaptability across the entire pixel circuit despite reduced driving current.
Solution Approach 2:
The patent employs composite gate insulating layer structures where multiple insulating materials are combined in specific sequences. The first gate insulating layer uses a composite structure optimized for the driving transistor's voltage requirements, while the second gate insulating layer uses a different composite structure optimized for the switching transistor. These composite material structures enable the circuit to maintain adequate voltage ranges with reduced driving current.
3Reliability
If different gate insulating layers are used for driving and switching transistors, then device characteristics are optimized, but the manufacturing process becomes more complex
Solution Approach 1:
The gate insulating layer structure is segmented into distinct first and second gate insulating layers, each positioned over specific transistor regions. The first gate insulating layer is formed over the driving transistor region, and the second gate insulating layer is formed over the switching transistor region. This segmentation allows different material compositions and thicknesses to be applied to different transistors while maintaining a systematic, repeatable manufacturing process.
Solution Approach 2:
The patent resolves the complexity issue by organizing the different gate insulating layers in the vertical dimension rather than requiring lateral differentiation. The first gate insulating layer is positioned at a first vertical level over the driving transistor, and the second gate insulating layer is positioned at a second vertical level over the switching transistor. This vertical stacking approach simplifies the manufacturing process compared to lateral differentiation, as layers can be formed sequentially using standard thin-film deposition techniques.
Data Source
AI summary
A display device includes: a first semiconductor layer on a first buffer layer, and including a first active layer; a first gate insulating layer on the first semiconductor layer, and covering the first active layer; a first conductive layer on the first gate insulating layer, and including a first gate electrode; a second conductive layer on the first conductive layer, and including a first source/drain electrode; a first interlayer insulating layer on the first conductive layer; a second semiconductor layer on the first interlayer insulating layer, and including a second active layer; a second gate insulating layer on the second semiconductor layer, and covering the second active layer; and a third conductive layer on the second gate insulating layer, and including a second gate electrode and a second source/drain electrode. The first gate insulating layer and the second gate insulating layer include different insulating materials from each other.