SiC Device Asymmetric Orientation Defect Management
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Solution Overview
Problem
The high cost and defect propagation issues in manufacturing electronic devices using monocrystalline SiC substrates with low defect densities, particularly due to basal plane dislocations, limit the efficiency and affordability of these devices.
Innovation Solution
A method involving a stack of a monocrystalline SiC support substrate with a high defect density and a monocrystalline SiC layer with a lower defect density, where the layer's second face is inclined at least 1° relative to the support substrate's (11-20) plane, allowing for epitaxial growth and defect management through ion implantation and separation techniques to maintain high-quality layer integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin layer of monocrystalline SiC with low defect density is transferred onto a monocrystalline SiC support with high defect density, then manufacturing cost is reduced, but defects propagate from the support into the thin layer during subsequent high thermal budget steps
Solution Approach 1:
The patent applies asymmetry by creating a deliberate orientation mismatch between the support substrate and the thin SiC layer. The support substrate has a first orientation while the thin layer has a second orientation that differs by at least 1 degree, as specified in claim 1. This asymmetric orientation relationship prevents defect propagation from the high-defect-density support into the low-defect-density thin layer during thermal processing, while still allowing the cost benefits of using a high-defect-density support substrate.
2Reliability
If the orientation difference between support substrate and thin layer is increased to prevent defect propagation, then defect density in the layer is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies partial action by implementing a minimum orientation difference threshold of at least 1 degree between the support substrate and the thin SiC layer, as specified in claim 1. This partial angular adjustment is sufficient to block defect propagation pathways during thermal processing, yet small enough to be achieved through standard wafer bonding and alignment techniques without requiring complex manufacturing processes.
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 reduces manufacturing costs while maintaining low defect densities in the SiC layer, preventing defect propagation and ensuring high-quality electronic components with reduced BPD densities, suitable for power electronic components.
Implementation Method 1
forming a single crystal SiC layer (20) bonded to the support substrate (12), the layer (20) comprising a second face (34, 42, 54) facing the first face (14), the first face (14) corresponding to a plane (11-20) of the SiC monocrystal of the support substrate (12) and the second face (34, 42, 54) corresponding to a plane inclined at least 1° with respect to the plane (11-20) of the SiC single crystal of the layer (20)
Data Source
Figure 1~2C
Figure 2D~2G
Figure 3A~3D
AI summary
This description relates to an electronic device comprising a stack of a single-crystal SiC substrate (12) having a first face (14) and a single-crystal SiC layer (20) comprising a second face (22) opposite the first face. The first face corresponds to a plane (11-20) of the SiC single crystal of the substrate, and the second face corresponds to a plane inclined at least 1° to the plane (11-20) of the SiC single crystal of the layer (20).