Substrate-Free SiC Epitaxial Power Semiconductors for Lower Loss
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Solution Overview
Problem
Power semiconductor devices fabricated with wide bandgap materials like silicon carbide often suffer from increased series resistance and conduction losses due to the presence of a silicon carbide substrate.
Innovation Solution
The development of semiconductor devices that utilize a wide bandgap epitaxial layer without a silicon carbide substrate, where the epitaxial layer is mounted in a flip chip configuration on a submount, providing a thermal path for heat dissipation that does not include a semiconductor substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon carbide substrate is used to fabricate power semiconductor devices, then the devices can be manufactured with wide bandgap materials, but the series resistance increases and conduction losses increase
Solution Approach 1:
The patent extracts and removes the silicon carbide substrate from the device structure, retaining only the necessary epitaxial layer. This elimination of the substrate directly reduces the series resistance and conduction losses while maintaining the device's functional performance through alternative support structures.
2Stability of the object's composition
If a silicon carbide substrate is used to provide mechanical support, then the device structure is stable, but the thermal performance deteriorates due to increased bulk resistivity
Solution Approach 1:
The silicon carbide substrate is removed from the structure, eliminating the thermal resistance associated with bulk substrate conduction. The device achieves structural stability through alternative means (such as bonding to a submount or carrier) while benefiting from improved thermal performance through direct heat dissipation paths.
3Temperature
If the epitaxial layer is mounted in a flip chip configuration on a submount, then the thermal path is improved for heat dissipation, but the device complexity increases
Solution Approach 1:
Instead of the conventional configuration where the substrate provides both mechanical support and thermal management, the patent inverts the approach by removing the substrate and mounting the epitaxial layer directly to a submount in flip chip configuration. This reversal creates optimized thermal paths while the submount assumes the mechanical support function.
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 bulk resistivity and improves thermal performance by eliminating the silicon carbide substrate, thereby enhancing the efficiency and reliability of power semiconductor devices.
Implementation Method 1
The second surface of the epitaxial silicon carbide layer provides at least a portion of a thermal path configured to dissipate heat from the wide bandgap epitaxial layer
Data Source
AI summary
Power semiconductor devices are provided. In one example, a semiconductor device includes a wide bandgap epitaxial layer. The wide bandgap epitaxial layer includes silicon carbide. The wide bandgap epitaxial layer has a first surface and an opposing second surface. The semiconductor device includes a first contact on the first surface of the wide bandgap epitaxial layer. The second surface is not in direct or indirect contact with a silicon carbide substrate.