Modified AlN Source for Downfall Prevention in Face-Up Crystal Growth
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Solution Overview
Problem
The challenge of growing high-quality aluminum nitride (AlN) single crystals with large diameters is hindered by anisotropic growth, thermal expansion coefficient differences with SiC substrates leading to cracks, and the face-down method causing substrate deflection and downfall during crystal growth.
Innovation Solution
A modified aluminum nitride source with specific bulk density and porosity, manufactured through heat treatment and etching, is used in a face-up method to suppress downfall and defects during crystal growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a face-down method is used for AlN crystal growth, then the substrate can be supported, but the substrate deflects and damages due to weight
Solution Approach 1:
The patent inverts the conventional face-down growth method to a face-up method, where the substrate is positioned with its growth surface facing upward. This inversion eliminates substrate deflection and damage caused by weight while enabling stable large-diameter crystal growth without mechanical failure
2Reliability
If the AlN source is positioned above the substrate in face-up method, then substrate deflection is prevented, but the source adheres to the substrate causing downfall
Solution Approach 1:
The patent modifies physical parameters of the AlN source including bulk density (2.0-3.0 g/cm³) and open porosity (5-20%), and controls particle size distribution (d10, d50, d90 values) to prevent source material from adhering to the substrate while maintaining stability in the face-up configuration
3Area of stationary object
If AlN single crystal wafer diameter is increased, then large-diameter substrate is obtained, but anisotropic growth limits quality
Solution Approach 1:
The patent inverts the growth configuration to face-up method, which enables simultaneous achievement of large wafer diameter (6 inches or more) and high crystal quality by preventing substrate deflection and source downfall that previously limited scaling
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 enables the production of high-quality AlN single crystals with reduced defects by minimizing substrate deflection and polycrystallization, facilitating large-diameter crystal growth.
Implementation Method 1
a heat treatment step of heat treating an aluminum nitride source to produce an aluminum nitride sintered body
Implementation Method 2
an etching step of etching the aluminum nitride sintered body
Data Source
AI summary
The purpose of the present is to provide a modified AlN source for suppressing downfall defects. This manufacturing method of a modified aluminum nitride source involves a heat treatment step for heat treating an aluminum nitride source and generating an aluminum nitride sintered body.