Thin Film Transistor Gate Dielectric Hydrogen Control
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Solution Overview
Problem
Current flexible electronic products face challenges in achieving foldability with small bending radii while maintaining manufacturing yield and product reliability.
Innovation Solution
A thin film transistor is developed with a flexible substrate, a semiconductor layer, a first gate, and a first gate dielectric layer where the hydrogen atom concentration of the gate dielectric layer is less than 6.5×10^20 atoms/cm^3, formed using a process that includes a polysilicon layer and a plasma-enhanced chemical vapor deposition (PECVD) process to ensure low hydrogen content, reducing Si—H bonding and potential electrical defects under bending stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate dielectric layer contains conventional hydrogen atom concentration, then the manufacturing process is simpler, but electrical defects occur under bending stress
Solution Approach 1:
The patent applies parameter changes by precisely controlling the hydrogen atom concentration in the gate dielectric layer to be less than 6.5×10^20 atoms/cm³. This is achieved through adjusting PECVD process parameters including silane flow ratio (5-20%), reaction pressure (200-500 mTorr), and temperature (200-400°C), thereby resolving the contradiction between reliability under bending and ease of manufacture
Solution Approach 2:
The patent implements preliminary action by pre-controlling the hydrogen atom concentration in the gate dielectric layer before the bending stress is applied. The low hydrogen concentration is established during the PECVD deposition process, preventing Si-H bond formation that would otherwise break under subsequent bending stress, thus ensuring electrical stability in advance
2Length of moving object
If the bending radius is reduced for flexible products, then the flexibility and compactness are improved, but the manufacturing yield and product reliability deteriorate
Solution Approach 1:
The patent resolves this contradiction by changing the chemical composition parameter of the gate dielectric layer, specifically maintaining hydrogen atom concentration below 6.5×10^20 atoms/cm³. This compositional change enables the transistor to maintain electrical stability even when bent to small radii (≥1 mm), as the reduced hydrogen content prevents bond breaking that would otherwise occur under such mechanical stress
Solution Approach 2:
The patent converts the potentially harmful effect of bending stress into a beneficial outcome by designing a gate dielectric layer with intrinsically low hydrogen content. The low hydrogen concentration prevents the formation of weak Si-H bonds that would break under bending, thereby transforming what would be a damaging mechanical stress into an opportunity to demonstrate enhanced device reliability and flexibility
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 solution allows for flexible electronic products with a small bending radius of at least 1 mm without significant changes in threshold voltage, enhancing the reliability and durability of the transistors by minimizing electrical defects caused by bond breaking in the gate dielectric layer.
Implementation Method 1
a plasma-enhanced chemical vapor deposition (PECVD) process to ensure low hydrogen content
Data Source
AI summary
A thin film transistor including a flexible substrate, a semiconductor layer, a first gate, and a first gate dielectric layer is provided. The semiconductor layer is located on the flexible substrate. The first gate is located on the flexible substrate and corresponds to a portion of the semiconductor layer. The first gate dielectric layer is located between the first gate and the semiconductor layer. The first gate dielectric layer is in contact with the semiconductor layer, and the hydrogen atom concentration of the first gate dielectric layer is less than 6.5×1020 atoms/cm3. A method of manufacturing the thin film transistor is also provided.