Oxide Semiconductor Transistor Oxygen Buffering for Display Uniformity
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Solution Overview
Problem
Transistors using oxide semiconductors exhibit characteristic variations in reliability tests due to processing temperature fluctuations, leading to defects such as display unevenness in display devices. Therefore, there is a need for improved transistor reliability in display devices.
Innovation Solution
A display device configuration that includes a transistor with a gate electrode on an insulating surface, a gate insulating layer, an oxide semiconductor layer overlapping the gate electrode, source/drain electrodes with a nitrogen-containing conductive layer, and an oxygen-containing insulating layer. This configuration enhances the reliability of the transistor by controlling oxygen diffusion and reducing characteristic variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transistors using oxide semiconductors are used in display devices, then high mobility and high pressure resistance are achieved, but characteristic variations occur due to processing temperature fluctuations leading to display unevenness
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the insulating layer (specifically oxygen content) to stabilize transistor characteristics. The insulating layer is designed to contain oxygen at specific concentrations (e.g., oxygen partial pressure during formation, or oxygen concentration of 1-50 at%) to compensate for oxygen loss during processing, thereby maintaining consistent transistor performance across different processing temperatures and preventing display unevenness.
Solution Approach 2:
The patent implements beforehand cushioning by pre-loading oxygen into the insulating layer during its formation process. This oxygen reservoir is prepared in advance to compensate for oxygen loss that will occur during subsequent processing steps such as heat treatment or plasma processing. The insulating layer acts as a buffer that releases oxygen when needed, stabilizing the oxide semiconductor layer and preventing characteristic variations before they can manifest as defects.
2Productivity
If processing temperature is increased to improve manufacturing efficiency, then productivity increases, but transistor characteristics vary leading to display unevenness
Solution Approach 1:
The patent changes the parameter of oxygen content in the insulating layer to enable higher processing temperatures without compromising transistor stability. By adjusting oxygen concentration parameters in the insulating layer, the system can withstand thermal stress during high-temperature processing while maintaining consistent transistor characteristics, thus achieving both high productivity and reliable display uniformity.
Solution Approach 2:
The insulating layer is prepared with excess oxygen content before processing to cushion against thermal degradation during high-temperature manufacturing steps. This pre-prepared oxygen buffer compensates for thermally-induced oxygen loss, allowing the production process to run at higher temperatures for improved efficiency without sacrificing transistor characteristic stability.
3Ease of manufacture
If oxygen diffusion is not controlled, then manufacturing process is simpler, but transistor characteristics become unstable causing display defects
Solution Approach 1:
The patent controls oxygen diffusion by changing the parameter of oxygen concentration in the insulating layer. Rather than adding complex diffusion barriers or multiple processing steps, the solution modifies the chemical composition parameter of the insulating layer itself, creating an oxygen gradient that naturally prevents excessive diffusion while maintaining manufacturing simplicity and achieving consistent transistor characteristics.
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
The proposed solution improves the reliability of the display device by stabilizing transistor characteristics, reducing defects such as display unevenness, and enhancing the overall performance of the display device.
Implementation Method 1
a first conductive layer containing nitrogen and a second conductive layer on the first conductive layer
Implementation Method 2
an insulating layer containing oxygen on the oxide semiconductor layer and the source/drain electrodes
Implementation Method 3
forming a transistor by performing a heat treatment
Data Source
AI summary
A display device comprising a transistor and a display element over the transistor, wherein the transistor includes a gate electrode on an insulating surface, a gate insulating layer on the gate electrode, and source/drain electrodes on the oxide semiconductor layer and the gate insulating layer, each including a first conductive layer containing nitrogen and a second conductive layer on the first conductive layer, and an insulating layer contains oxygen on the oxide semiconductor layer and the source/drain electrodes.