SiC Epitaxial Structure With Nitride Angle Adjustment Layer
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Solution Overview
Problem
The existing methods for manufacturing epitaxial structures on silicon carbide substrates with off-angle silicon faces result in poor epitaxial quality due to the extension of substrate properties to the nitride layers, affecting the performance of components like High Electron Mobility Transistors.
Innovation Solution
A method involving the deposition of a nitride angle adjustment layer through physical vapor deposition between the silicon carbide substrate and the first group III nitride layer, followed by additional nitride layers, to improve epitaxial quality by mitigating the off-angle effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an aluminum nitride layer is grown on a SiC substrate with off-angle silicon face through metal-organic chemical vapor deposition, then the HEMT structure can be formed, but the off-angle property extends to the AlN layer resulting in poor epitaxial quality
Solution Approach 1:
A nitride angle adjustment layer is introduced as an intermediary between the SiC substrate and the AlN layer. This intermediate layer has different crystal orientation characteristics that compensate for the off-angle substrate, preventing the extension of off-angle properties to the final AlN layer and improving epitaxial quality
Solution Approach 2:
The crystal orientation parameters of the nitride layer are changed by using a specifically oriented Si-face SiC substrate with a controlled off-angle (0.5-5 degrees). This parameter change in the intermediate nitride layer allows it to serve as an angle adjustment mechanism, improving the epitaxial quality of subsequent layers
2Productivity
If a silicon face with off-angle is used as growth face for epitaxy, then the HEMT device can be manufactured, but the epitaxial quality deteriorates due to substrate off-angle extension
Solution Approach 1:
The nitride angle adjustment layer acts as a mediator that decouples the relationship between substrate orientation and epitaxial layer quality. It absorbs the off-angle characteristics while providing a suitable growth surface for high-quality AlN layer formation
Solution Approach 2:
The Si-face SiC substrate with controlled off-angle is prepared in advance as a preliminary step. This pre-prepared substrate with specific orientation parameters enables the subsequent formation of high-quality nitride layers by controlling the initial crystal orientation
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 significantly enhances the epitaxial quality of both the first and second group III nitride layers, as evidenced by reduced root mean square roughness and full width at half maximum in X-ray diffraction analysis, effectively addressing the poor quality issues caused by off-angle substrates.
Implementation Method 1
deposit a nitride angle adjustment layer on the growth face of the SiC substrate through physical vapor deposition (PVD)
Data Source
AI summary
A method of manufacturing an epitaxial structure includes steps of: A: provide a silicon carbide (SiC) substrate, wherein a silicon face (Si-face) of the SiC substrate is taken as a growth face, and the growth face has an off-angle relative to the Si-face of the SiC substrate; B: deposit a nitride angle adjustment layer on the growth face of the SiC substrate through physical vapor deposition (PVD); C: deposit a first group III nitride layer on the nitride angle adjustment layer; and D: deposit a second group III nitride layer on the first group III nitride layer. Through the method of manufacturing the epitaxial structure, when the silicon face of the silicon carbide substrate has the off-angle, the problem of a poor epitaxial quality of the first group III nitride layer and a poor epitaxial quality of the second group III nitride layer could be effectively relieved.