Silicon Carbide Epitaxial Substrate for Basal Plane Dislocation Control
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Solution Overview
Problem
Existing silicon carbide epitaxial substrates face challenges in improving the reliability of silicon carbide semiconductor devices due to the presence of extended defects, particularly basal plane dislocations, which are exacerbated by temperature variations during film growth and cooling processes.
Innovation Solution
The silicon carbide epitaxial substrate is designed with a specific structure that includes a silicon carbide substrate and epitaxial film, featuring a first extended defect with a particle, triangular defect, and basal plane dislocation, where the epitaxial film thickness is 30 μm or more, and the basal plane dislocation's extended width is twice or more than the triangular defect's base width, with an area density of 3/cm² or less, and the film surface is inclined at 5° or less to the {0001} plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the epitaxial film thickness is increased to improve device performance, then the reliability improves, but the extended defect area increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the epitaxial film thickness to be 30 μm or more, and by controlling the cooling rate during solidification to be 10°C/min or less. These parameter adjustments optimize the balance between film thickness benefits and defect area minimization, resolving the contradiction between reliability improvement and extended defect area increase.
2Manufacturing precision
If the cooling rate is reduced to minimize thermal stress, then the basal plane dislocation density decreases, but the manufacturing time increases
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal cooling rate parameter of 10°C/min or less during the solidification process. This parameter change simultaneously achieves low basal plane dislocation density (3/cm² or less) and controls manufacturing time, balancing precision and efficiency.
3Reliability
If the epitaxial film thickness is increased to improve device performance, then the reliability improves, but the manufacturing cost increases
Solution Approach 1:
The patent resolves this contradiction by optimizing the epitaxial film thickness parameter to 30 μm or more, which improves device reliability while controlling manufacturing costs through efficient material utilization and reduced defect rates, making high-performance devices more cost-effective to produce.
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 structure effectively reduces the extended width of basal plane dislocations, enhancing the reliability of silicon carbide semiconductor devices by minimizing stress and improving performance.
Implementation Method 1
a basal plane dislocation originating from the particle and having a portion extending along a direction perpendicular to each of a thickness direction of the silicon carbide substrate and the off-direction
Implementation Method 2
a silicon carbide epitaxial film on the silicon carbide substrate
Data Source
AI summary
A silicon carbide epitaxial substrate includes a silicon carbide substrate, a silicon carbide epitaxial film. The silicon carbide epitaxial film is on the silicon carbide substrate. The first extended defect is in the silicon carbide epitaxial film. The first extended defect includes a particle, a triangular defect extending from the particle along an off-direction, and a basal plane dislocation originating from the particle and having a portion extending along a direction perpendicular to each of a thickness direction of the silicon carbide substrate and the off-direction. In the direction perpendicular to each of the thickness direction of the silicon carbide substrate and the off-direction, an extended width of the basal plane dislocation is twice or more a base width of the triangular defect. In a second main surface, an area density of the basal plane dislocation included in the first extended defect is 3/cm2 or less.