GaN Epitaxial Structure With Controlled Substrate Roughness
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Solution Overview
Problem
Existing epitaxial layers in GaN-based HEMT heterostructures for high-frequency and high-power applications suffer from high thermal resistance, which negatively impacts the operating performance of semiconductor devices.
Innovation Solution
The epitaxial structure of a semiconductor device is designed with a substrate having a surface roughness of 0<Ra≤5 nm, allowing for the growth of a high-quality epitaxial layer without the need for a buffer layer, thereby reducing thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thick buffer layer is used in the epitaxial structure, then the lattice mismatch between substrate and epitaxial layer is compensated, but the thermal resistance increases significantly
Solution Approach 1:
The patent changes the surface roughness parameter of the substrate from conventional smooth (Ra<1nm) to controlled roughness (0.5nm<Ra≤5nm). This parameter change enables direct epitaxial growth without buffer layers while maintaining lattice matching, thereby resolving the contradiction between lattice matching and thermal resistance
Solution Approach 2:
The patent extracts and eliminates the buffer layer from the traditional epitaxial structure. By using substrates with controlled surface roughness, the buffer layer function is integrated into the substrate surface characteristics, removing the source of thermal resistance while maintaining lattice matching
2Manufacturing precision
If a buffer layer is introduced to improve epitaxial layer quality, then the crystal quality improves, but the device complexity and manufacturing steps increase
Solution Approach 1:
The patent removes the buffer layer from the epitaxial structure, simplifying the device architecture. The substrate surface with controlled roughness (0.5nm<Ra≤5nm) directly supports high-quality epitaxial growth, eliminating unnecessary structural layers
Solution Approach 2:
The substrate surface is given multiple functions: it provides both the mechanical support and the crystal template for epitaxial growth. The controlled roughness enables the substrate to simultaneously ensure lattice matching and direct growth, replacing the buffer layer's function
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 reduces thermal resistance and improves heat dissipation in the epitaxial layer, enhancing the operating performance of semiconductor devices by eliminating the need for a thick buffer layer.
Implementation Method 1
epitaxial layers need to be epitaxially grown on the substrate
Implementation Method 2
a surface roughness of one side the substrate close to the epitaxial layer is Ra, wherein 0<Ra≤5 nm
Data Source
AI summary
The disclosure discloses an epitaxial structure of a semiconductor device, as well as a manufacturing method thereof, and a semiconductor device. Therein, the epitaxial structure includes a substrate and an epitaxial layer located on one side of the substrate, and a surface roughness of one side the substrate close to the epitaxial layer is Ra, wherein 0<Ra≤5 nm. In the epitaxial structure of a semiconductor device as well as the manufacturing method thereof and the semiconductor device provided by the disclosure, by setting the surface roughness Ra on one side of the epitaxial growth of the substrate to satisfy 0<Ra≤5 nm, a high-quality epitaxial layer can be directly epitaxially grown on the substrate, eliminating the need to arrange a thicker buffer layer and thus reducing thermal resistance, which improves the operating performance of the semiconductor device.