Composite Group III Nitride Substrate With Hexagonal Nanopores
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Solution Overview
Problem
It is challenging to obtain a group III nitride substrate with a large area and high quality due to its high melting point and large nitrogen saturation vapor pressure, making it difficult to achieve a homogeneous substrate with minimal lattice and thermal mismatch.
Innovation Solution
A composite substrate is manufactured by growing a group III nitride layer on a supporting substrate, bonding it to a target substrate with a dielectric layer, removing the supporting substrate, and forming hexagonal nanopores on the N-face of the group III nitride layer, which alleviates lattice and thermal mismatch, reducing parasitic capacitance and enabling homoepitaxial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a group III nitride substrate is grown directly with large area, then the substrate area increases, but the quality deteriorates due to high melting point and large nitrogen saturation vapor pressure causing inhomogeneity
Solution Approach 1:
The substrate is segmented into a supporting substrate and a group III nitride layer that can be separately optimized. The supporting substrate provides mechanical support and large area, while the nitride layer is grown epitaxially with controlled thickness and quality, eliminating the constraint of direct large-area growth
Solution Approach 2:
A composite substrate structure is formed by bonding the group III nitride layer to a different supporting substrate material. This composite structure allows each layer to contribute its optimal properties: the nitride layer provides device-quality material with controlled composition, while the supporting substrate provides mechanical stability and large area
2Manufacturing precision
If the supporting substrate is removed to enable lateral epitaxial growth, then device quality improves, but the structural stability deteriorates
Solution Approach 1:
The supporting substrate is removed only after the group III nitride layer has been fully grown and bonded to the target substrate with dielectric layer. This preliminary bonding ensures structural stability is maintained during the removal process, and the target substrate with dielectric layer provides new mechanical support for subsequent lateral epitaxial growth
3Reliability
If hexagonal nanopores are formed on the N-face to reduce stress, then device reliability improves, but the manufacturing complexity increases
Solution Approach 1:
Hexagonal nanopores are introduced into the group III nitride layer to create a porous structure that reduces stress and dislocation density. The nanopores act as stress relief features and facilitate lateral epitaxial growth, improving device reliability despite the additional manufacturing steps required for pore 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
The method results in a high-quality group III nitride substrate with reduced defects, allowing for the growth of devices with improved reliability and reduced stress through lateral epitaxial growth and nanopore design.
Implementation Method 1
growing a group III nitride layer on a supporting substrate
Implementation Method 2
bonding the group III nitride layer to a target substrate
Implementation Method 3
removing the supporting substrate
Implementation Method 4
forming a plurality of hexagonal nanopores arranged at intervals on a side, away from the target substrate, of the group III nitride layer
Data Source
AI summary
A manufacturing method includes: growing a group III nitride layer on a supporting substrate; bonding the group III nitride layer to a target substrate having a dielectric layer on a surface of the target substrate; removing the supporting substrate; and forming a plurality of hexagonal nanopores arranged at intervals on a side, away from the target substrate, of the group III nitride layer. The technical solutions of the present disclosure may reduce a stress caused by lattice mismatch and thermal mismatch between the group III nitride layer and a substrate, thereby improving a quality of a group III nitride substrate.