Silicon Carbide Wafer Omega Angle Control
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Solution Overview
Problem
The challenge is to produce silicon carbide wafers with improved mechanical properties, excellent crystallinity, and fewer defects, as existing methods struggle to achieve uniform crystal characteristics and minimize defects like basal plane dislocation.
Innovation Solution
A silicon carbide wafer with a specific omega angle distribution across its surface, where the first peak omega angle in the [1-100] direction is within ±0.5° to ±0.05°, and the second peak omega angle in the [11-20] direction is within ±0.8° to ±0.8°, ensuring uniform crystal growth and reduced defects, is manufactured using a method involving a holder with high thermal conductivity and precise X-ray diffraction analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional seed sublimation method is used for silicon carbide crystal growth, then high growth rate is achieved, but uniform crystal characteristics and defect minimization cannot be obtained
Solution Approach 1:
The patent applies different temperature conditions to different regions of the crystal growth system. Specifically, the seed crystal is maintained at a temperature lower by 10-100°C than the raw material powder, creating a controlled temperature gradient that promotes uniform crystal growth while maintaining high growth rate. This local temperature differentiation resolves the contradiction between productivity and manufacturing precision.
2Productivity
If higher temperature is used for crystal growth, then growth rate increases, but defects such as basal plane dislocation increase
Solution Approach 1:
The patent changes the temperature parameter distribution in the crystal growth system. By maintaining the seed crystal temperature 10-100°C lower than the raw material powder temperature, the method optimizes the temperature parameters to achieve both high growth rate and low defect density. This parameter optimization resolves the contradiction between productivity and reliability.
3Reliability
If single crystal SiC is produced for high breakdown voltage applications, then device performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary action by preparing the seed crystal with specific temperature conditions before the actual crystal growth process. By pre-establishing the temperature gradient (seed crystal 10-100°C lower than raw material), the method simplifies the overall manufacturing process while ensuring high breakdown voltage characteristics in the final product. This preliminary temperature setup reduces manufacturing complexity while maintaining high reliability.
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 approach results in silicon carbide wafers with enhanced mechanical properties, reduced warping, and minimized cracking due to defects, providing overall improved rigidity and reduced defects, even under external stress.
Implementation Method 1
a holder with high thermal conductivity
Implementation Method 2
precise X-ray diffraction analysis
Data Source
AI summary
Disclosed are a silicon carbide wafer and a method of manufacturing the same. The silicon carbide wafer includes an upper surface and a lower surface, the upper surface includes a first target region, the first target region being within 85% of a radius of the upper surface based on a center of the upper surface, a first peak omega angle measured at intervals of 15 mm in a first direction in the first target region is within −1° to +1° based on a peak omega angle measured at the center of the upper surface, and the first direction is a [1-100] direction and a direction passing through the center of the upper surface.