Corundum Laminate Middle Layer for Low-Defect Crystal Growth
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Solution Overview
Problem
Conventional methods for producing high-quality corundum-structured crystals using mist CVD and ELO techniques face challenges such as lattice mismatch and complex, costly processes that result in high crystal defects and increased production costs.
Innovation Solution
A laminate structure comprising a crystal substrate, a middle layer with a mixture of amorphous and crystal regions, and a crystal layer, where the middle layer acts as a seed crystal to reduce dislocation defects, and a method involving the formation of mixture gases to deposit these layers without the need for a dedicated mask, allowing for low-cost, high-quality crystal film production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ELO method with amorphous mask is used to suppress crystal defects, then crystal quality is improved, but device complexity and production cost increase due to additional mask formation apparatus and photolithography steps
Solution Approach 1:
The invention combines the mask layer and the functional crystal layer into a single integrated structure. The middle layer serves both as a dislocation-blocking mask and as a seed layer for epitaxial growth of the corundum-structured crystal layer, eliminating the need for separate mask formation apparatus and photolithography steps while maintaining crystal quality.
Solution Approach 2:
The middle layer with mixed amorphous and crystal regions performs multiple functions simultaneously: (1) acts as a mask to block dislocation defects from the substrate, (2) serves as a seed crystal layer for epitaxial growth, and (3) provides a transition zone between the substrate and the corundum crystal layer. This multi-functionality reduces process complexity while achieving high crystal quality.
2Manufacturing precision
If conventional ELO method with amorphous mask is used to suppress crystal defects, then crystal quality is improved, but production cost increases due to additional apparatus and process steps
Solution Approach 1:
The invention combines the mask layer and the functional crystal layer into a single integrated structure. The middle layer serves both as a dislocation-blocking mask and as a seed layer for epitaxial growth of the corundum-structured crystal layer, eliminating the need for separate mask formation apparatus and photolithography steps while maintaining crystal quality.
3Productivity
If mist CVD method is used to grow gallium oxide crystal, then crystal growth is achieved, but crystal defects are not sufficiently suppressed due to lattice mismatch and substrate quality issues
Solution Approach 1:
The invention segments the crystal growth process into three distinct layers: (1) a crystal substrate providing the initial growth platform, (2) a middle layer with mixed amorphous and crystal regions that blocks dislocations, and (3) a corundum-structured crystal layer grown epitaxially on the middle layer. This segmentation allows each layer to perform its specific function, achieving both productivity and high crystal quality.
Solution Approach 2:
The middle layer with mixed amorphous and crystal regions acts as an intermediary between the substrate and the corundum crystal layer. It mediates the lattice mismatch issue by providing a transition zone that blocks dislocation defects while still enabling epitaxial growth of the high-quality crystal layer.
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 laminate achieves a high-quality corundum-structured crystal layer with reduced defects and lower production costs, suitable for semiconductor devices, by using a middle layer with controlled crystal and amorphous region proportions and silicon incorporation to inhibit dislocation defects.
Implementation Method 1
the amorphous region in the middle layer stops extension of dislocation defect attributable to the substrate
Implementation Method 2
the crystal region may be an epitaxially grown layer from a crystal plane of the crystal substrate
Implementation Method 3
Mist Chemical Vapor Deposition (Mist CVD. Hereinafter, this method may also be referred to as 'mist CVD method') has been developed by which crystal is grown on a substrate
Data Source
AI summary
The present invention is a laminate including: a crystal substrate; a middle layer formed on a main surface of the crystal substrate, the middle layer containing a mixture of an amorphous region in an amorphous phase and a crystal region in a crystal phase having a corundum structure mainly made of a first metal oxide; and a crystal layer formed on the middle layer and having a corundum structure mainly made of a second metal oxide. Thus, provided is a laminate having high-quality corundum-structured crystal with sufficiently suppressed crystal defects.