AlN Substrate Growth on Through-Hole SiC for Large-Diameter Crystals
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Solution Overview
Problem
Existing methods face challenges in manufacturing large-diameter aluminum nitride (AlN) substrates with excellent crystallinity due to regions where AlN crystals do not grow during sublimation, limiting the diameter and quality of semiconductor substrates.
Innovation Solution
A method involving through hole formation on a silicon carbide (SiC) underlying substrate, followed by crystal growth with a temperature gradient, to form an aluminum nitride layer, promoting lateral and longitudinal growth and improving crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If AlN crystals are grown on an underlying substrate via sublimation method, then crystal growth occurs, but there are regions where AlN crystals do not grow, limiting substrate diameter and crystallinity
Solution Approach 1:
The invention segments the underlying substrate by forming through-holes at specific positions, dividing the substrate surface into growth regions and non-growth regions. This segmentation allows AlN crystals to grow laterally from nucleation points around the through-holes, enabling complete coverage of the entire substrate area including regions that would otherwise remain uncovered.
Solution Approach 2:
The invention transitions from two-dimensional surface growth to three-dimensional growth by utilizing the vertical dimension through through-holes. AlN crystals grow laterally along the substrate surface from nucleation points at the through-hole edges, and also grow vertically to fill the through-holes, creating a multi-directional growth pattern that ensures complete substrate coverage.
2Area of stationary object
If through holes are formed in SiC underlying substrate, then lateral growth of AlN layer is promoted and large diameter substrate is achieved, but strained layer is introduced during through hole formation
Solution Approach 1:
The invention performs preliminary action by forming through-holes in the SiC substrate before performing the AlN crystal growth. This preliminary structuring of the substrate creates predetermined nucleation sites that guide subsequent crystal growth, ensuring that AlN crystals grow laterally from the through-hole edges and achieve complete substrate coverage with excellent crystallinity.
Solution Approach 2:
The invention changes physical parameters during the growth process, specifically utilizing temperature gradient control. By maintaining appropriate temperature differences between the source and substrate, and controlling growth pressure and atmosphere, the invention promotes lateral growth along the substrate surface while managing the effects of the through-holes and minimizing strain accumulation.
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
Enables the production of large-diameter AlN substrates with enhanced crystallinity by utilizing SiC substrates with through holes, reducing dislocations and achieving a diameter equivalent to the SiC substrate.
Implementation Method 1
a crystal growth step of forming an aluminum nitride layer on a silicon carbide underlying substrate having through holes
Implementation Method 2
the crystal growth step is a step of heating such that a temperature gradient is formed along a vertical direction of the silicon carbide underlying substrate
Implementation Method 3
a method for growing AlN crystals on a seed crystal substrate arranged in a crystal growth chamber in a crystal growth vessel provided in a reaction vessel via a vapor phase growth method
Data Source
AI summary
An object of the present invention is to provide a novel technique capable of manufacturing a large-diameter AlN substrate.The present invention is a method for manufacturing an AlN substrate, including a crystal growth step S30 of forming an AlN layer 20 on a SiC underlying substrate 10 having through holes 11. In addition, the present invention is a method for forming an AlN layer including the through hole formation step S20 of forming the through holes 11 in the SiC underlying substrate 10 before forming the AlN layer 20 on the SiC underlying substrate 10.