SiC Composite Substrate Structure for Lower On-State Resistance
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Solution Overview
Problem
Power semiconductor devices fabricated using monocrystalline silicon carbide substrates face challenges due to high substrate resistance, leading to increased conduction losses and limited thickness reduction without risking breakage during handling.
Innovation Solution
The use of a wide bandgap semiconductor wafer with a polycrystalline silicon carbide substrate and a wide bandgap epitaxial layer, where the epitaxial layer is attached to the substrate using techniques such as plasma bonding, allowing for the fabrication of power semiconductor devices with reduced substrate resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If monocrystalline silicon carbide substrates are used, then manufacturing precision is improved, but substrate resistance increases leading to higher conduction losses
Solution Approach 1:
The substrate system is segmented into two distinct parts: a monocrystalline silicon carbide epitaxial layer for device fabrication and a separate polycrystalline silicon carbide substrate for mechanical support. This segmentation allows each layer to optimize its properties independently, resolving the contradiction between manufacturing precision and conduction losses.
Solution Approach 2:
The invention employs a composite substrate structure combining monocrystalline and polycrystalline silicon carbide layers. The monocrystalline epitaxial layer provides high manufacturing precision for devices, while the polycrystalline substrate provides mechanical strength with lower resistance, thus reducing conduction losses while maintaining device quality.
2Reliability
If substrate thickness is reduced to minimize breakage risk, then reliability is improved, but manufacturing flexibility is limited
Solution Approach 1:
By separating the functional epitaxial layer from the mechanical substrate, the invention enables independent optimization of thickness. The polycrystalline substrate can be made thicker for mechanical reliability and breakage resistance, while the monocrystalline epitaxial layer maintains optimal thinness for device performance, thus improving reliability without limiting manufacturing flexibility.
Solution Approach 2:
The polycrystalline silicon carbide substrate acts as an intermediary mechanical support layer that bears the mechanical stress and prevents breakage, allowing the monocrystalline epitaxial layer to be processed with greater thickness flexibility without compromising device reliability during handling.
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 power semiconductor devices with lower on-state resistance and reduced risk of breakage during handling, while also enhancing the performance and efficiency of the devices.
Implementation Method 1
The epitaxial layer is attached to the substrate using techniques such as plasma bonding
Data Source
AI summary
Semiconductor wafers, methods, and semiconductor devices are provided. In one example, a semiconductor wafer includes a polycrystalline silicon carbide substrate. The semiconductor wafer includes a wide bandgap epitaxial layer on the polycrystalline silicon carbide substrate.