Silicon Carbide Substrate Heat Treatment After Laser Through-Hole Processing
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Solution Overview
Problem
Laser processing of semiconductor substrates can introduce strains that lead to dislocations, which are undesirable and can be transferred to growth layers during epitaxial growth, necessitating a method to remove these strained layers.
Innovation Solution
A method involving laser processing of silicon carbide substrates followed by heat treatment to remove the strained layers, which includes forming through holes and etching in a quasi-closed silicon atmosphere to create a temperature gradient and planarize the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If laser processing is performed to form through holes in the silicon carbide substrate, then the substrate structure is improved for epitaxial growth, but strained layers are introduced that cause dislocations
Solution Approach 1:
The process is divided into two distinct stages: first performing laser processing to create the through hole structure, then performing a separate heat treatment process to remove the strained layers. This segmentation allows each process to be optimized independently, achieving both structural formation and quality maintenance.
Solution Approach 2:
Heat treatment is performed as a preliminary action before epitaxial growth to remove strained layers from the substrate. By eliminating the strained layers in advance, the substrate is prepared in a state that prevents dislocation formation during subsequent epitaxial growth, ensuring high reliability.
2Reliability
If heat treatment is performed to remove strained layers, then substrate quality is improved, but additional processing time is required
Solution Approach 1:
The heat treatment process combines multiple functions: it removes strained layers from the substrate while simultaneously preparing the surface for epitaxial growth. By merging these functions into a single processing step, the overall process time is reduced compared to performing separate treatment steps.
3Manufacturing precision
If laser processing is used to remove parts of the substrate, then precise patterning is achieved, but strains are introduced into the substrate
Solution Approach 1:
The strain layers generated by laser processing are not simply discarded but are selectively removed through heat treatment. This converts the harmful effect of strain introduction into a beneficial process where the strain layers serve as a target for selective removal, ultimately improving substrate quality by eliminating the dislocation-prone regions.
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
Effectively removes the strained layers introduced during laser processing, reducing dislocations and improving the substrate quality for subsequent epitaxial growth by creating a favorable crystal growth environment.
Implementation Method 1
a processing step of performing laser processing of removing a part of a silicon carbide substrate by irradiating the silicon carbide substrate with a laser
Implementation Method 2
a strained layer removal step of removing a strained layer introduced into the silicon carbide substrate by the processing step via heat treating the silicon carbide substrate
Implementation Method 3
it is possible to form a temperature gradient in a lateral direction serving as a driving force in a crystal growth proceeding along an a-axis direction
Data Source
AI summary
The problem to addressed by the present invention is that of providing a novel technique that can remove a strained layer introduced into a silicon carbide substrate by laser processing. The present silicon carbide substrate manufacturing method involves a processing step for performing laser processing to remove part of a silicon carbide substrate by irradiating the silicon carbide substrate with a laser, and a strained layer removal step for removing a strained layer that was introduced in the silicon carbide substrate by the aforementioned processing step involving heat treatment of the silicon carbide substrate. In this way, the present invention, which is a method of removing a strained layer introduced into a silicon carbide substrate by laser processing, involves a strained layer removal step for heat treating the silicon carbide substrate.