Nickel-Seeded Laser Crystallization of Amorphous Silicon
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Solution Overview
Problem
The existing methods for crystallizing amorphous silicon into poly-silicon films for display devices, such as OLED and LCD, face limitations in increasing grain size due to laser irradiation, which restricts the improvement of electrical characteristics and can cause substrate deformation.
Innovation Solution
A method involving the formation of nickel particles on an amorphous silicon layer, followed by thermal diffusion and low-energy laser irradiation to create a poly-crystal silicon layer with larger grains, acting as seeds for crystal growth, thereby improving the electrical characteristics and reducing substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-energy laser irradiation is used to crystallize amorphous silicon, then crystallization is achieved, but substrate deformation occurs and grain size is limited
Solution Approach 1:
Nickel particles are deposited on the amorphous silicon layer before laser irradiation to serve as crystal seeds. This preliminary action enables the silicon to crystallize more easily and form larger grains during low-energy laser irradiation, avoiding the need for high-energy lasers that cause substrate deformation.
Solution Approach 2:
Nickel particles act as an intermediary substance that facilitates the crystallization process. The nickel particles serve as nucleation sites that promote silicon crystal growth, allowing crystallization to occur with lower laser energy and preventing direct high-energy laser-substrate interaction that causes deformation.
2Manufacturing precision
If high-energy laser irradiation is used to increase grain size, then crystallization is achieved, but energy consumption increases and substrate damage occurs
Solution Approach 1:
Nickel particles are deposited in advance on the amorphous silicon layer to create nucleation sites for crystal growth. This preliminary preparation allows the silicon to crystallize into larger grains during low-energy laser irradiation, eliminating the need for high-energy lasers and reducing overall energy consumption.
Solution Approach 2:
The invention changes the energy parameter of the laser from high to low by introducing nickel particles as crystal seeds. The presence of nickel particles alters the crystallization mechanism, enabling grain growth at lower energy levels and thus reducing energy consumption while achieving larger grain sizes.
3Reliability
If conventional laser crystallization is used, then amorphous silicon is converted to poly-silicon, but electrical characteristics are limited due to small grain size
Solution Approach 1:
Nickel particles are deposited before laser irradiation to serve as crystal seeds. This preliminary action promotes the formation of larger silicon grains during crystallization, which directly improves the electrical characteristics of the resulting poly-silicon layer by reducing grain boundary effects.
Solution Approach 2:
Nickel particles mediate the crystallization process by providing nucleation sites that facilitate grain growth. This intermediary mechanism enables the formation of larger grains with better electrical properties, overcoming the limitation of small grain sizes in conventional laser crystallization.
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 enhances the electrical characteristics of thin-film transistors and display devices by forming poly-crystal silicon layers with larger grains, while minimizing substrate deformation and energy usage during crystallization.
Implementation Method 1
converting the backup amorphous silicon layer into an amorphous silicon layer by thermally processing the backup amorphous silicon layer so as to diffuse the nickel particles throughout said backup amorphous silicon layer
Implementation Method 2
irradiating the amorphous silicon layer with energy from a laser
Implementation Method 3
crystallizing an amorphous silicon layer into the poly-silicon film by irradiation from a laser
Data Source
AI summary
A crystallization method, a method of manufacturing a thin-film transistor, and a method of manufacturing a display device are provided. The crystallization method includes: forming a backup amorphous silicon layer on a substrate, forming nickel particles on the backup amorphous silicon layer, converting the backup amorphous silicon layer into an amorphous silicon layer by thermally processing the backup amorphous silicon layer so as to diffuse the nickel particles throughout said backup amorphous silicon layer; and irradiating the amorphous silicon layer with energy from a laser.