Laser Beam Profile Shaping for Defect-Free Silicon Crystallization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of defects in polycrystalline silicon films due to hydrogen explosion during laser crystallization of amorphous silicon films, which can deteriorate the quality of display devices.
Innovation Solution
A laser crystallization apparatus and method that includes a beam generator, a beam converter with a predetermined rotation angle, and a beam concentrator, which divides and condenses the laser beam into specific beam profiles with stiffness areas and a high-intensity area, allowing for controlled irradiation of the amorphous silicon film to minimize hydrogen explosion and prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional laser beam is used for crystallization, then the crystallization process is simple, but hydrogen explosion occurs causing defects in the polycrystalline silicon film
Solution Approach 1:
The laser beam is divided into multiple sub-beams by the beam converter, creating a segmented beam structure with multiple stiffness areas. This segmentation allows controlled dehydrogenation across different regions, preventing hydrogen accumulation that leads to explosion while maintaining effective crystallization.
Solution Approach 2:
The beam profile is designed with different intensity characteristics in different regions - stiffness areas at the edges and a high-intensity area in the center. This local quality variation enables selective dehydrogenation in edge regions while maintaining crystallization efficiency in the central region, resolving the contradiction between preventing hydrogen explosion and ensuring film quality.
2Reliability
If the beam converter is added to modify the beam profile, then hydrogen explosion is prevented, but the device complexity increases
Solution Approach 1:
The beam converter performs multiple functions simultaneously: it divides the laser beam into sub-beams, creates the specific beam profile with stiffness areas, controls the dehydrogenation process, and prevents hydrogen explosion. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving the desired reliability improvement.
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 controlled dehydrogenation process reduces the occurrence of defects in polycrystalline silicon films, ensuring improved quality and reliability of display devices by gradually reducing hydrogen content during crystallization.
Implementation Method 1
a beam converter dividing the input laser beam incident from the beam generator into a plurality of sub laser beams and disposed to have a predetermined rotation angle with respect to an optical axis
Implementation Method 2
a beam converter dividing the input laser beam incident from the beam generator into a plurality of sub laser beams and disposed to have a predetermined rotation angle with respect to an optical axis
Implementation Method 3
a beam concentrator condensing the plurality of sub laser beams and outputting an output laser beam having a beam profile having a predetermined beam width
Implementation Method 4
irradiating a laser to an amorphous silicon film to form a polycrystalline silicon film
Implementation Method 5
irradiating a laser beam to an amorphous silicon film using a laser crystallization apparatus
Implementation Method 6
after crystallization, a hydrogen explosion occurs on a surface of the polycrystalline silicon film
Implementation Method 7
laser crystallization apparatus capable of preventing an occurrence of defects in a polycrystalline silicon film
Data Source
AI summary
Provided is a laser crystallization apparatus including a beam generator generating an input laser beam, a beam converter dividing an input laser beam incident from a beam generator into a plurality of sub laser beams and disposed to have a predetermined rotation angle with respect to an optical axis parallel to a traveling direction of an input laser beam, and a beam concentrator condensing a plurality of sub laser beams and outputting an output laser beam having a beam profile having a predetermined beam width. Accordingly, a width of a stiffness area of a beam profile of an input laser beam may increase and a width of a high intensity area may decrease. Accordingly, the number of shots for the stiffness area at specific point of an amorphous silicon film may increase. Accordingly, a gradual dehydrogenation effect on an amorphous silicon film may be implemented. Accordingly, occurrence of defects in a polycrystalline silicon film formed by laser crystallization may be minimized or prevented.