Group-III Nitride Substrate Growth Layout for Warping Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Group-III element nitride substrates obtained by epitaxial growth on different material base substrates are prone to warping.
Innovation Solution
A Group-III element nitride substrate with controlled carrier concentration and defect density gradients in specific directions, produced through a method involving seed crystal growth and base substrate removal, where the seed crystal substrate is arranged to align with the rotation axis of the mounting table during crystal growth to ensure uniform material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If epitaxial growth is performed on a base substrate made of different material, then a Group-III element nitride substrate can be obtained, but warping is liable to occur
Solution Approach 1:
The invention changes the material composition parameters of the substrate by forming a multi-layer structure with alternating high-aluminum and low-aluminum AlGaN layers. This compositional parameter variation allows control of thermal expansion and lattice mismatch, thereby suppressing warping while maintaining the benefits of epitaxial growth on different material base substrates
Solution Approach 2:
The invention uses a composite material structure consisting of alternating AlGaN layers with different aluminum compositions. This composite approach combines materials with different properties to achieve both manufacturability and warping suppression, as the layered composite structure compensates for stress and distortion during growth and operation
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 effectively suppresses warping, ensuring uniform crystal growth and improved substrate quality, enabling large-size substrate production with reduced warping and enhanced electrical characteristics.
Implementation Method 1
a center of the seed crystal substrate is spaced apart from a rotation axis of the mounting table, and wherein the seed crystal substrate is arranged so that an angle formed by an off-angle direction of the seed crystal film of the seed crystal substrate and a normal of the rotation axis of the mounting table that passes through the center of the seed crystal substrate is substantially 0° in plan view
Implementation Method 2
growing a Group-III element nitride crystal on the seed crystal film of the seed crystal substrate by a flux method
Data Source
AI summary
A Group-III element nitride substrate includes a first main surface and a second main surface facing each other. The Group-III element nitride substrate has a first direction, which extends in a surface direction, and in which a carrier concentration or a defect density is decreased from a first end portion side to a second end portion side, in a substrate surface of the Group-III element nitride substrate.