SiC Ingot Curvature Control for BPD Reduction
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Solution Overview
Problem
Existing methods for manufacturing SiC ingots fail to sufficiently suppress basal plane dislocation (BPD) defects, which can lead to device performance degradation due to the high curvature of the atomic arrangement plane.
Innovation Solution
A method involving the measurement of the atomic arrangement plane's curvature and adjusting crystal growth conditions to achieve a saddle-type shape, where the convexity of the second growth front is greater than the first, and the height difference between growth fronts is controlled to reduce curvature, thereby minimizing BPD density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional crystal growth methods are used to manufacture SiC ingots, then manufacturing process simplicity is maintained, but basal plane dislocation (BPD) density remains high due to high curvature of the atomic arrangement plane
Solution Approach 1:
The invention changes the parameters of crystal growth conditions, specifically controlling the convexity of growth fronts at different stages. By setting the convexity of the second growth front to be greater than the first growth front when the amount of crystal growth in the center of the seed crystal is 7 mm, the curvature of the atomic arrangement plane is reduced, thereby suppressing BPD formation and improving manufacturing precision.
Solution Approach 2:
The invention introduces a feedback mechanism by measuring the curving direction of the atomic arrangement plane during crystal growth and using this measurement to adjust the crystal growth conditions. This closed-loop control allows dynamic adjustment of growth parameters to maintain optimal convexity differences between growth fronts, effectively reducing BPD density while managing process complexity.
2Manufacturing precision
If the convexity of growth fronts is not controlled during crystal growth, then manufacturing process simplicity is maintained, but the curvature of the atomic arrangement plane increases leading to higher BPD density
Solution Approach 1:
The invention modifies the crystal growth parameters by establishing specific relationships between the convexity of different growth fronts. By controlling that the convexity of the second growth front exceeds the first growth front at a specific growth stage (7 mm center growth), the atomic arrangement plane curvature is effectively reduced, improving manufacturing precision without requiring overly complex equipment.
3Reliability
If BPD density is not suppressed, then manufacturing process simplicity is maintained, but device performance deteriorates due to slip on the basal plane
Solution Approach 1:
The invention implements a feedback-based control system that measures the curving direction of the atomic arrangement plane and adjusts crystal growth conditions accordingly. This measurement and control mechanism directly addresses BPD suppression, thereby improving device reliability by preventing slip on the basal plane, while the added complexity is managed through systematic monitoring and adjustment protocols.
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 results in SiC ingots with reduced curvature and lower BPD density, leading to higher quality SiC wafers and improved device performance.
Implementation Method 1
a crystal growth step of performing crystal growth using the SiC single crystal as a seed crystal
Data Source
AI summary
A method of measuring a SiC ingot includes a measuring step of measuring a curving direction of an atomic arrangement plane of a SiC single crystal at least along a first direction passing through a center in plan view and a second direction intersecting with the first direction to obtain a shape of the atomic arrangement plane; and a crystal growth step of performing crystal growth using the SiC single crystal as a seed crystal, in which in a case where the shape of the atomic arrangement plane measured in the measuring step is a saddle type, a crystal growth condition in the crystal growth step is set such that a convexity of a second growth front at the end of crystal growth becomes larger than a convexity of a first growth front when an amount of crystal growth in the center of the seed crystal is 7 mm.