Transistor Stopper Hydrogen Capture for Leakage Control
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Solution Overview
Problem
Existing transistors in display devices face issues with reliability, increased size, non-uniform current levels, leakage current, and high material usage, along with environmental impacts from manufacturing processes.
Innovation Solution
A transistor design incorporating an oxide semiconductor material with a stopper structure that includes a hydrogen-capturing component, such as titanium, to stabilize the active layer and reduce the active layer's thickness, thereby enhancing reliability and reducing the transistor's size and material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the active layer thickness is reduced to improve transistor size and reliability, then the transistor size and defect rate are reduced, but the on-state current uniformity and leakage current control deteriorate
Solution Approach 1:
A stopper layer is introduced as an intermediary component between the active layer and source/drain electrodes. This stopper layer captures hydrogen atoms that would otherwise diffuse into the active layer and cause defects. By positioning this hydrogen-capturing intermediary at the interface, the patent resolves the contradiction by enabling thin active layer design while maintaining current uniformity and controlling leakage through hydrogen concentration management.
Solution Approach 2:
The patent changes the chemical composition parameter of the stopper layer by incorporating hydrogen-capturing materials (such as tungsten, molybdenum, or titanium). This parameter change enables the stopper to actively manage hydrogen concentration at the active layer interface, thereby maintaining electrical performance even when the active layer thickness is reduced for smaller transistor size.
2Reliability
If conventional transistor structures are used to maintain current flow, then the structure is simple, but leakage current increases and reliability decreases
Solution Approach 1:
The stopper layer serves as a hydrogen-capturing intermediary positioned at the interface between the active layer and source/drain regions. This intermediary structure prevents hydrogen-induced defects that cause leakage current, thereby improving reliability. The stopper is integrated into the existing transistor fabrication flow with minimal additional process steps, balancing the added structural complexity against significant reliability gains.
3Ease of manufacture
If standard manufacturing processes are used, then the process is established, but material consumption and greenhouse gas emissions are high
Solution Approach 1:
The patent changes the material composition parameter by selecting stopper layer materials (tungsten, molybdenum, titanium) that can be deposited using established PVD or CVD processes. These materials enable hydrogen capture functionality while being compatible with existing semiconductor manufacturing infrastructure, thereby reducing the need for process retooling and associated environmental impacts.
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 design maintains uniform on-state current levels, prevents off-state current increases, reduces leakage current, and minimizes environmental impact by decreasing greenhouse gas emissions, while improving the reliability and reducing defect rates in display devices.
Implementation Method 1
a stopper disposed to overlap the first and second source drain regions of the active layer and connected to each of the first and second source drain electrodes
Data Source
AI summary
Disclosed is a display device including a substrate including a display area and a non-display area, a first transistor disposed in the display area and including a first gate electrode and a first active layer, and a second transistor disposed in the display area, and including a second gate electrode, a first source drain electrode, a second source drain electrode, and a stopper, wherein the stopper contacts the second active layer at a bottom of each of the first source drain electrode and the second source drain electrode of the second transistor, and a display device including the same.