Epitaxial Substrate Crystal Plane Conversion for Crack-Free GaN Growth
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Solution Overview
Problem
The use of silicon substrates in GaN-based semiconductor devices leads to thermal and lattice mismatches, causing cracking of the GaN-based semiconductor film and hindering the production of high-performance devices.
Innovation Solution
A manufacturing method for an epitaxial substrate involves patterning a substrate to form trenches, creating a transition layer, and performing crystal plane transformation processing based on the trench shape, specifically transforming the transition layer into a single crystal layer with a (111) crystal plane surface using high-temperature annealing and optionally alkaline solution processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a silicon substrate is used for GaN-based semiconductor devices, then thermal conductivity and electrical conductivity are improved, but thermal mismatch and lattice mismatch cause cracking of the GaN-based semiconductor film
Solution Approach 1:
The patent introduces a transition layer between the silicon substrate and the GaN-based semiconductor film. This transition layer serves as an intermediary that gradually transforms the crystal structure from amorphous/polycrystalline to single crystal, thereby reducing the thermal and lattice mismatch between silicon and GaN, and preventing cracking of the semiconductor film.
Solution Approach 2:
The patent employs high-temperature annealing processing to change the physical and chemical parameters of the transition layer. By controlling the annealing temperature and duration, the transition layer undergoes crystal plane transformation, changing its crystal structure from amorphous or polycrystalline to single crystal, which resolves the mismatch issue.
2Area of stationary object
If a silicon substrate is used for GaN-based semiconductor devices, then large substrate size is achieved, but lattice mismatch causes cracking of the GaN-based semiconductor film
Solution Approach 1:
The transition layer acts as an intermediary structure that accommodates the lattice mismatch between large silicon substrates and GaN-based materials. The gradual crystal transformation in the transition layer distributes the stress, preventing cracking even on large-area substrates.
Solution Approach 2:
The patent segments the interface between silicon substrate and GaN-based semiconductor film by introducing a transition layer. This segmentation allows the interface to be divided into multiple regions with different crystal structures, reducing the overall mismatch stress across the large substrate area.
3Manufacturing precision
If high-temperature annealing processing is performed on the transition layer, then the transition layer is transformed into a single crystal layer, but processing complexity increases
Solution Approach 1:
The patent utilizes high-temperature annealing to change the thermal and structural parameters of the transition layer. By optimizing the annealing temperature, time, and atmosphere parameters, the transition layer is transformed into a single crystal layer with controlled crystal orientation, achieving high manufacturing precision.
Solution Approach 2:
The patent replaces complex mechanical crystal growth methods with thermal field-based annealing processing. Instead of using sophisticated mechanical systems for crystal growth, the invention uses controlled thermal energy to induce crystal transformation, simplifying the processing system while achieving single crystal formation.
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 method facilitates the growth of high-quality epitaxial structures by overcoming lattice mismatch issues, enabling the production of high-performance semiconductor devices with improved thermal conductivity and electrical properties.
Implementation Method 1
performing crystal plane transformation processing on the transition layer based on a shape of the trench, so as to transform the transition layer into a single crystal layer
Implementation Method 2
the crystal plane transformation processing includes at least high-temperature annealing processing... the high-temperature annealing processing is laser annealing processing
Implementation Method 3
performing the alkaline solution processing on a surface, away from the substrate, of the original single crystal layer by using an alkaline solution, to obtain the single crystal layer
Data Source
AI summary
Disclosed are a manufacturing method for an epitaxial substrate, an epitaxial substrate, and a semiconductor structure. The manufacturing method includes: patterning a substrate to form a trench; manufacturing a transition layer in the trench, and performing crystal plane transformation processing on the transition layer based on a shape of the trench, so as to transform the transition layer into a single crystal layer, where a surface, away from the substrate, of the single crystal layer is a (111) crystal plane. Based on different shapes of the trench on the substrate, the transition layer is controlled to obtain a single crystal layer of a specific crystal plane after the crystal plane transformation processing, and a surface, away from the substrate, of the single crystal layer, is a (111) crystal plane. The (111) crystal plane of the single crystal layer facilitates subsequent epitaxial manufacturing of a semiconductor structure.