Laminate Gate Insulator for Bend-Stable Thin Film Transistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thin film transistors face challenges in maintaining high mobility and durability against bending due to variations in threshold voltage and mobility degradation, particularly when using inorganic silicon compounds as gate insulating layers.
Innovation Solution
A thin film transistor structure incorporating a laminate gate insulating layer with a first organic polymer compound film and a second inorganic silicon compound film, where the second gate insulating film has a thickness of 2 nm to 40 nm and a hydrogen content of 2 at% to 18 at%, formed using plasma CVD, sandwiched between the semiconductor and gate electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic silicon compound gate insulating layer is used, then high dielectric property value is achieved, but threshold voltage variation and mobility degradation occur
Solution Approach 1:
The gate insulating layer is formed as a composite structure combining an organic polymer compound (first gate insulating film) and an inorganic silicon compound (second gate insulating film). The organic layer provides flexibility and buffers threshold voltage shifts, while the inorganic layer maintains high dielectric property. This composite approach resolves the contradiction by integrating the advantages of both material types to achieve stable threshold voltage and controlled mobility.
Solution Approach 2:
The hydrogen content of the inorganic silicon compound layer is precisely controlled within 2 at% to 15 at%, and the thickness is optimized between 2 nm to 30 nm. By adjusting these parameters, the gate insulating layer achieves optimal dielectric properties while minimizing threshold voltage variation and mobility degradation, directly addressing the manufacturing precision challenge.
2Speed
If the gate insulating layer is made thinner to reduce capacitance, then switching speed improves, but durability against bending decreases
Solution Approach 1:
The organic polymer compound layer serves as a flexible buffer that absorbs bending stress, protecting the thinner inorganic silicon compound layer from damage. This composite structure enables the gate insulating layer to be thin enough for high switching speed while maintaining bending durability through the mechanical protection provided by the organic layer.
Solution Approach 2:
The organic polymer compound gate insulating film acts as a flexible protective shell that accommodates substrate bending without cracking the brittle inorganic silicon compound layer. This flexible film structure allows the device to maintain high switching speed with thin gate insulating layer while achieving bending durability.
3Reliability
If a laminate structure with organic and inorganic films is used, then field-effect mobility and bending durability are improved, but device complexity increases
Solution Approach 1:
The gate insulating layer is segmented into two functional films: an organic polymer compound film for flexibility and threshold voltage stability, and an inorganic silicon compound film for high dielectric property and mobility enhancement. This segmentation allows each layer to perform its specific function optimally while together they improve field-effect mobility and bending durability.
Solution Approach 2:
By optimizing the thickness (2 nm to 30 nm) and hydrogen content (2 at% to 15 at%) of the inorganic silicon compound layer, the patent achieves high field-effect mobility without requiring excessive layer complexity. The controlled parameters ensure that the laminate structure delivers performance benefits while maintaining manufacturing feasibility.
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 enhances field-effect mobility, reduces threshold voltage variations, and suppresses mobility degradation caused by bending, while maintaining a high dielectric property value and flexibility.
Implementation Method 1
forming a second gate insulating film including an inorganic silicon compound such that the second gate insulating film is sandwiched between the first gate insulating film and the semiconductor layer by plasma CVD
Data Source
AI summary
A gate insulating layer includes a first gate insulating film including an organic polymer compound and covering a second part of a support surface and a gate electrode layer, and second gate insulating film including an inorganic silicon compound and sandwiched between the first gate insulating film and a semiconductor layer. The second gate insulating film has a thickness of 2 nm or greater and 30 nm or less, and the second gate insulating film has a hydrogen content of 5 at % or more and 13 at % or less so as to enhance the electrical durability of the thin film transistor against bending of the flexible substrate.