Through-Hole Substrate Growth for Large-Diameter AlN Crystals
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Solution Overview
Problem
Existing methods face challenges in manufacturing semiconductor substrates with large diameters and excellent crystallinity, particularly when growing materials like AlN crystals on substrates such as AlN or SiC using sublimation methods.
Innovation Solution
A method involving through hole formation in the underlying substrate followed by crystal growth, including steps like laser drilling and heat treatment to remove strained layers, allows for the formation of a growth layer with a diameter equivalent to the underlying substrate, utilizing temperature gradients for lateral and longitudinal growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a growth layer is formed on an underlying substrate without through holes, then the manufacturing process is simpler, but the substrate diameter is limited and crystallinity is poor
Solution Approach 1:
Through holes are formed in the underlying substrate before the crystal growth step. This preliminary action removes regions that would otherwise generate dislocations and defects, allowing the subsequent growth layer to form with superior crystallinity across the entire substrate area.
Solution Approach 2:
The underlying substrate is divided into multiple regions by forming through holes that extend through its thickness. This segmentation removes specific problematic areas (where through holes are formed) while preserving the overall substrate structure, enabling improved crystallinity in the growth layer without requiring complete substrate replacement.
2Area of stationary object
If simple sublimation method is used to grow crystals, then the process is easier, but regions where crystals do not grow are formed, limiting substrate diameter
Solution Approach 1:
Through holes are formed in the underlying substrate before crystal growth to pre-establish regions that will not generate dislocations. This preliminary structuring enables the crystal growth method to successfully produce large-diameter substrates with uniform crystallinity across the entire area, including regions that would otherwise fail to grow properly.
Solution Approach 2:
The substrate structure is modified by introducing through holes, changing its physical parameters (creating voids and altering thermal/electrical conductivity distribution). This parameter change enables the crystal growth process to achieve uniform material properties across a larger substrate diameter than would be possible with an intact substrate.
3Manufacturing precision
If through holes are formed in the underlying substrate, then large-diameter substrates with excellent crystallinity can be obtained, but strained layers are introduced during through hole formation
Solution Approach 1:
The strained layers introduced by through hole formation are not merely tolerated but actively utilized. The strain fields generated by the through holes and associated dislocation structures are converted into beneficial effects that promote lateral crystal growth and improve overall crystallinity in the growth layer, transforming a harmful byproduct into a useful mechanism.
Solution Approach 2:
The through holes act as intermediary structures that mediate between the substrate and the growth layer. They serve as controlled defect sites that influence dislocation dynamics and crystal growth patterns, ultimately leading to improved crystallinity in the final product while managing the inevitable strain introduced during fabrication.
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 enables the production of large-diameter semiconductor substrates with improved crystallinity by promoting bonding and reducing dislocation defects, specifically in materials like AlN on SiC substrates.
Implementation Method 1
the through hole formation step is a step of forming the through holes by irradiating the underlying substrate with a laser
Implementation Method 2
the strained layer removal step is a step of removing the strained layer of the underlying substrate by heat treatment
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
Implementation Method 4
the crystal growth step is a step of heating such that a temperature gradient is formed along a vertical direction of the underlying substrate
Data Source
AI summary
An object of the present invention is to provide a novel technique capable of manufacturing a large-diameter semiconductor substrate. The present invention is a method for manufacturing a semiconductor substrate including a crystal growth step S30 of forming a growth layer 20 on an underlying substrate 10 having through holes 11. In addition, the present invention is a method for forming a growth layer 20 including the through hole formation step S10 of forming through holes 11 in the underlying substrate 10 before forming the growth layer 20 on a surface of the underlying substrate 10.