TFT Grain Size Control via Nickel-Induced Crystallization
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Solution Overview
Problem
The manufacturing process for organic light emitting displays is complex and costly due to the need for separate processes to form switching and driving TFTs with different silicon channel region grain sizes, leading to increased costs and reduced efficiency.
Innovation Solution
A method involving the formation of amorphous silicon layers with self-assembled monolayers and nickel particles, where metal-induced crystallization is used to create TFTs with varying grain sizes in a single process, allowing for the simultaneous formation of switching and driving TFTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate processes are used to manufacture switching TFT and driving TFT with different grain sizes, then the required performance characteristics are achieved, but manufacturing complexity and costs increase
Solution Approach 1:
The patent combines the manufacturing of switching TFT and driving TFT into a single unified process. By forming both transistor types simultaneously from a common amorphous silicon layer using the same crystallization conditions, the method eliminates the need for separate manufacturing processes while achieving the required performance characteristics for both transistor types.
Solution Approach 2:
The patent applies local quality by creating different grain sizes in different regions of the same silicon layer through selective masking. The switching TFT region receives a first mask pattern that allows crystallization to form small grain sizes suitable for switching characteristics, while the driving TFT region receives a second mask pattern that allows crystallization to form large grain sizes suitable for driving characteristics.
2Device complexity
If amorphous silicon TFT is used for both switching and driving functions, then manufacturing process is simplified, but electron mobility and reliability are insufficient for driving transistor
Solution Approach 1:
The patent changes the grain size parameter of the crystallized silicon to achieve different performance characteristics. By controlling the crystallization process to produce small grain sizes in the switching TFT region and large grain sizes in the driving TFT region, the method achieves high electron mobility and reliability for the driving transistor while maintaining the simplified single-process manufacturing approach.
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 approach simplifies the manufacturing process, reduces costs, and improves the efficiency of organic light emitting displays by enabling the formation of TFTs with controlled grain sizes in fewer steps, enhancing the overall performance and reliability of the devices.
Implementation Method 1
forming an SAM (self-assembled monolayer) having a hydrophobic property on the first amorphous region
Implementation Method 2
wherein a larger amount of nickel particles than on the SAM are dispersed on the second amorphous region using a hydrophilicity difference between the second amorphous region and the SAM
Implementation Method 3
vaporizing the SAM through an annealing process
Implementation Method 4
simultaneously performing metal induced crystallization in which the nanoparticles are used as a medium, to crystallize the first and second amorphous regions
Data Source
AI summary
Provided is a method of manufacturing a driving-device for a unit pixel of an organic light emitting display having an improved manufacturing process in which the driving device can be manufactured with a smaller number of processes and in simpler processes. The method includes: forming an amorphous silicon layer including a first amorphous region and a second amorphous region disposed on the same plane of a substrate; forming an SAM (self-assembled monolayer) having a hydrophobic property on the first amorphous region; coating an aqueous solution in which nickel particles are dispersed, on the second amorphous region and the SAM, wherein a larger amount of nickel particles than on the SAM are dispersed on the second amorphous region using a hydrophilicity difference between the second amorphous region and the SAM; vaporizing the SAM through an annealing process and simultaneously performing metal induced crystallization in which the nanoparticles are used as a medium, to crystallize the first and second amorphous regions and to form first and second crystallization regions; patterning the first and second crystallization regions to form first and second channel regions; and forming first and second electrodes on the first and second channel regions.