GaN-on-SiC Bonded Semiconductor Body for High Breakdown Strength
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Solution Overview
Problem
GaN/AlGaN based HEMTs face limitations in breakdown strength and reliability due to lattice mismatch and defects when grown on Si substrates, leading to poor dynamic on-resistance and current collapse, especially under high electric fields.
Innovation Solution
A composite semiconductor body is formed by bonding a SiC-based semiconductor body with a GaN-based semiconductor body using adhesion layers, avoiding epitaxial growth on SiC, which reduces lattice mismatch and defects, and allowing for epitaxial growth of GaN on a planarized surface, thus improving breakdown strength and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If GaN material is epitaxially grown on Si substrate, then manufacturing cost is reduced, but breakdown strength and reliability deteriorate due to lattice mismatch and defects
Solution Approach 1:
The invention divides the semiconductor structure into separate components: a Si substrate with SiC buffer layer and a separate GaN-based layer structure. These segments are grown independently on their respective substrates and then bonded together, avoiding the direct epitaxial growth of GaN on Si that causes lattice mismatch and defects.
Solution Approach 2:
The invention introduces SiC buffer layers as intermediary layers between the Si substrate and the GaN-based structure. These buffer layers act as a transition zone that reduces the lattice mismatch and defect propagation, enabling reliable integration of GaN on Si substrate.
2Reliability
If GaN material is epitaxially grown on SiC substrate, then breakdown strength is improved, but manufacturing complexity increases due to lattice mismatch and defect formation
Solution Approach 1:
The invention separates the GaN growth process from the SiC substrate, growing GaN on a separate template substrate first. This segmentation allows independent optimization of each layer structure and simplifies the manufacturing process by avoiding direct epitaxial growth on the final substrate.
Solution Approach 2:
The invention performs preliminary growth of the GaN-based layer structure on a template substrate before final assembly. This preliminary action allows for better control of layer quality and reduces defects, simplifying subsequent manufacturing steps.
3Reliability
If GaN/AlGaN HEMT is designed with high breakdown voltage capability, then power transistor performance is improved, but dynamic on-resistance and current handling deteriorate due to defects and current collapse
Solution Approach 1:
The SiC buffer layers serve as intermediary layers that reduce defect formation at the interface between Si substrate and GaN-based HEMT structure. This reduces current collapse and improves dynamic on-resistance while maintaining high breakdown voltage capability.
Solution Approach 2:
The invention uses a composite structure combining Si substrate, SiC buffer layers, and GaN-based HEMT layers. This composite material approach leverages the advantages of each material: Si for cost-effectiveness, SiC for thermal management and defect reduction, and GaN for high electron mobility and breakdown voltage.
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 enhances the breakdown strength and reliability of high electron mobility transistors by minimizing defects and lattice mismatch, resulting in improved on-resistance and current handling capabilities.
Implementation Method 1
A first adhesion layer is formed on the first semiconductor body. A second adhesion layer is formed on the second semiconductor body. The first and the second semiconductor bodies are bonded together by adhering the first and the second adhesion layers to one another.
Data Source
AI summary
A first semiconductor body including type IV semiconductor material is provided. A second semiconductor body including type III-V semiconductor material is provided. A first adhesion layer is formed on the first semiconductor body. A second adhesion layer is formed on the second semiconductor body. The first and the second semiconductor bodies are bonded together by adhering the first and the second adhesion layers to one another.