SiC Buffer Layer on Silicon Substrate for Semiconductor Growth
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Solution Overview
Problem
Current semiconductor materials face challenges due to lattice and thermal expansion mismatches between substrates and films, leading to defects and reduced performance in electronic devices, with existing substrates like Si and sapphire causing strain and defects in nitride semiconductor layers.
Innovation Solution
A method for producing a SiC-containing film on a Si substrate by etching the Si substrate to remove native oxide and epitaxially growing a SiC film at temperatures below 1000°C using techniques such as plasma sputtering, chemical vapor deposition, or reactive atomic layer deposition, which reduces crystal defects and improves film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nitride semiconductor layer is grown on a Si substrate, then the substrate is readily available and inexpensive, but large numbers of dislocations and cracks occur due to stress caused by difference in thermal expansion coefficient or lattice constant
Solution Approach 1:
A SiC buffer layer is introduced as an intermediary between the Si substrate and the nitride semiconductor layer. This buffer layer serves as a mediator that reduces the lattice mismatch and thermal expansion coefficient difference between Si and nitride semiconductor, thereby reducing dislocations and cracks while maintaining the use of inexpensive Si substrates
Solution Approach 2:
The patent employs a composite structure consisting of Si substrate + SiC buffer layer + nitride semiconductor layer. This composite material approach allows combining the advantages of different materials: the low cost and ease of manufacture of Si substrate with the lattice-matched properties of SiC, achieving both economic and quality objectives
2Adaptability or versatility
If a film is grown on a substrate with different lattice constant, then the substrate can be used for various applications, but strain and defects are generated in the film
Solution Approach 1:
The SiC buffer layer acts as an intermediary that gradually transitions from the Si substrate lattice structure to the nitride semiconductor lattice structure, reducing strain and defects while maintaining versatility in substrate selection
3Reliability
If oxide substrates such as ZnO are used to grow semiconducting films, then some promise is shown for reduced defects, but the substrates react with by-products during epitaxial growth
Solution Approach 1:
The SiC buffer layer serves as a sacrificial or temporary layer that can be optimized and removed if necessary, allowing the use of inexpensive Si substrates while achieving high film quality without the reactivity issues of oxide substrates
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
The method results in high-quality SiC-on-Si films with reduced crystal defects, enabling the production of efficient electronic devices with improved performance and reliability by minimizing strain and defects in the semiconductor layers.
Implementation Method 1
etching a Si substrate to remove any native oxide
Implementation Method 2
epitaxially growing a first film on the Si substrate at temperatures below 1000° C., wherein the first film comprises SiC
Implementation Method 3
plasma sputtering
Implementation Method 4
chemical vapor deposition
Data Source
AI summary
A method for growing a SiC-containing film on a Si substrate is disclosed. The SiC-containing film can be formed on a Si substrate by, for example, plasma sputtering, chemical vapor deposition, or atomic layer deposition. The thus-grown SiC-containing film provides an alternative to expensive SiC wafers for growing semiconductor crystals.