Grooved Crystalline TFT Structure for Higher Mobility Channels
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Solution Overview
Problem
The mobility of thin film transistors needs to be improved to enable effective integration of integrated circuits on glass substrates, which is currently hindered by low transistor performance.
Innovation Solution
A thin film transistor design featuring a crystalline active pattern with grooves on contact portions and a heat-retaining layer, where the grooves facilitate seed crystal formation and slow heat dissipation during crystallization, resulting in larger crystalline grains and reduced boundaries, thereby enhancing mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thin film transistor structures are used, then manufacturing is simpler, but mobility is insufficient for integrated circuit integration
Solution Approach 1:
The patent applies preliminary action by pre-forming grooves in the contact portions before the crystallization process. These grooves serve as predetermined sites that guide crystal grain formation and growth during subsequent laser annealing, ensuring that large crystal grains form in the channel region without requiring complex post-processing steps.
Solution Approach 2:
The patent implements local quality by creating grooves specifically in the contact portions rather than uniformly across the entire active layer. This localized structural modification concentrates crystal nucleation sites where they are most beneficial, allowing the channel region to develop large crystal grains while maintaining selective control over the crystallization process.
2Productivity
If rapid crystallization is used, then manufacturing time is reduced, but crystal grain size is insufficient
Solution Approach 1:
The grooves are formed in advance before crystallization, serving as pre-positioned nucleation sites. During rapid laser annealing, crystals preferentially form at these groove locations and grow outward, ensuring that even with fast processing speeds, large crystal grains develop in the channel region because the growth starts from controlled positions rather than randomly.
Solution Approach 2:
The patent utilizes parameter changes by controlling the laser annealing conditions (wavelength, power, scanning speed) to match the specific geometry of the grooves. The groove dimensions and depth are optimized to work with specific laser parameters, creating a synergistic effect that enables rapid crystallization while maintaining large grain sizes through controlled thermal fields during the phase transition.
3Reliability
If small crystal grains form in the channel, then manufacturing is easier, but mobility is reduced
Solution Approach 1:
The grooves are strategically positioned in the contact portions, creating localized nucleation sites that direct crystal growth toward the channel region. This results in large crystal grains specifically forming where needed (in the channel) while the contact portions maintain their groove structures, achieving selective crystal grain control without requiring different manufacturing processes for different regions.
Solution Approach 2:
By pre-forming the groove pattern before crystallization, the patent establishes a template that guides crystal grain development. This preliminary structuring ensures that during subsequent processing, large grains form in the channel region automatically, eliminating the need for complex real-time control or post-processing steps to achieve the desired crystal structure.
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 improves the mobility of thin film transistors by forming large-sized crystalline grains, reducing boundaries, and facilitating the integration of integrated circuits on insulating substrates, thus reducing manufacturing costs and enhancing display panel performance.
Implementation Method 1
the seed crystals grow toward the channel before crystallization and cooperate with the heat-retaining layer to make heat dissipation of a pre-crystallization channel slower
Implementation Method 2
by defining the groove in at least one of the two contact portions of the crystalline active pattern, it is conducive to forming seed crystals at a position where the groove is located during a process of crystallization
Data Source
AI summary
The present application provides a thin film transistor and an electronic device. The thin film transistor includes: a crystalline active pattern, wherein the crystalline active pattern includes a channel and two contact portions, and the two contact portions are connected to opposite two sides of the channel in a direction intersecting a thickness direction of the crystalline active pattern; a groove located on at least one of the two contact portions and extending in the thickness direction of the crystalline active pattern; a source electrode and a drain electrode connected to the two contact portions, respectively; and an insulating layer being in contact with the channel.