Poly-Silicon TFT Manufacturing via Laser Annealing and Through Holes
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Solution Overview
Problem
Current thin film transistor (TFT) manufacturing methods for OLED screens using amorphous silicon are inefficient due to low electron mobility and complex, costly processes involving direct formation on transparent substrates and electrical connections.
Innovation Solution
A TFT manufacturing method involving a transparent substrate with a gate electrode and data line, insulation layers, and amorphous semiconductor layers, where a through hole connects the source and drain electrodes directly to the data line, and laser irradiation enhances lattice ordering, allowing for poly-silicon electrode formation and simplified processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous silicon TFT is used for OLED screen driving, then the manufacturing process is simpler, but the electron mobility is too low to satisfy current driving requirements
Solution Approach 1:
The patent changes the crystalline structure parameter of the semiconductor material from amorphous to poly-crystalline state. This parameter change transforms the material properties, achieving high electron mobility (comparable to single-crystal silicon) while maintaining the low-temperature processing advantages of amorphous silicon, thus resolving the contradiction between manufacturing simplicity and electrical performance
Solution Approach 2:
The patent employs a composite approach by forming a poly-crystalline semiconductor layer on top of an amorphous semiconductor layer. The amorphous layer serves as a buffer and nucleation substrate, while the poly-crystalline layer provides high mobility channels. This composite structure combines the advantages of both material states to achieve both ease of manufacture and high reliability
2Adaptability or versatility
If TFT is directly formed on transparent substrate with multi-laminated structure, then the device integration is achieved, but the working process becomes complicated and cost increases
Solution Approach 1:
The patent merges the formation of the active semiconductor layer and the source/drain electrodes into a single integrated process. The poly-crystalline semiconductor layer is formed to simultaneously create the active region and the electrode structures, eliminating the need for separate electrode formation steps and reducing overall process complexity while maintaining device integration
Solution Approach 2:
The poly-crystalline semiconductor layer serves multiple functions: it acts as the active switching region, forms the source and drain electrodes, and provides electrical connection to the transparent substrate. This multi-functionality reduces the number of separate components and manufacturing steps, simplifying the overall working process while achieving complete device integration
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 method reduces processing costs by simplifying the formation of source and drain electrodes and improving electrical characteristics by increasing electron mobility through poly-silicon usage and lattice ordering.
Implementation Method 1
irradiating the amorphous semiconductor layer by laser to increase an ordering degree of a lattice arrangement of the amorphous semiconductor layer
Implementation Method 2
irradiating the amorphous semiconductor layer by laser to increase an ordering degree of a lattice arrangement
Data Source
AI summary
The present invention provides a thin film transistor (TFT) manufacturing method and a TFT, a source electrode or drain electrode of the TFT is electrically connected to a data line directly during a forming process by providing a through hole in a surface above the data line of the TFT, so as to save the process cost. Further, the source electrode and drain electrode of the TFT are also manufactured with poly-silicon rather than metal material used in prior art, processing steps are simplified, thereby further saving the process cost.