Sapphire-Based α-Ga2O3 Films With AlGaO Strain Buffering
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Solution Overview
Problem
The growth of high-quality α-Ga2O3 films on sapphire substrates is hindered by lattice constant and thermal conductivity mismatches, leading to increased dislocation and cracking, which affects the application and development of semiconductor devices.
Innovation Solution
A pulsed epitaxial growth method is employed to form α-(AlxGa1-x)2O3 strain buffering layers on sapphire substrates, with 0.99≥x≥0.01, to alleviate strain and reduce defect density in the α-Ga2O3 epitaxial film, thereby improving crystal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If direct epitaxial growth of α-Ga2O3 on sapphire substrate is performed, then the crystal structure match is good, but lattice constant mismatch and thermal conductivity difference cause increased dislocation and cracking
Solution Approach 1:
The patent introduces an intermediate AlGaO layer between the sapphire substrate and the Ga2O3 epitaxial layer. This intermediate layer acts as a mediator that gradually transitions the lattice constant from the sapphire substrate to the Ga2O3 layer, reducing the abrupt mismatch. The AlGaO layer with graded aluminum content creates a progressive lattice transition, effectively reducing dislocation and cracking while maintaining the benefits of sapphire substrate.
Solution Approach 2:
The patent employs parameter changes by varying the aluminum content in the intermediate AlGaO layer. The aluminum content is gradually reduced from the substrate interface toward the Ga2O3 layer, creating a graded structure. This parameter gradient allows continuous adjustment of lattice constant and thermal properties, enabling smooth transition and reducing interface defects.
2Reliability
If high quality α-Ga2O3 films are grown on sapphire substrates, then device performance is improved, but the contradictory epitaxial temperature issues arise due to material property differences
Solution Approach 1:
The patent changes the epitaxial temperature parameter by growing the intermediate AlGaO layer at a lower temperature (400-600°C) than the Ga2O3 layer (500-700°C). This temperature gradient approach allows each layer to be grown at its optimal temperature, avoiding the contradiction where a single temperature cannot satisfy both materials' growth requirements.
Solution Approach 2:
The patent segments the epitaxial growth process into two distinct stages: first growing the intermediate AlGaO layer at a lower temperature, then growing the Ga2O3 layer at a higher temperature. This segmentation allows independent optimization of growth conditions for each material, resolving the temperature contradiction while ensuring high device performance.
3Manufacturing precision
If strain buffering layers are introduced to reduce dislocation, then film quality is improved, but the device complexity increases
Solution Approach 1:
The patent uses composite material structure by combining sapphire substrate, intermediate AlGaO layer, and Ga2O3 epitaxial layer into a single integrated device structure. This composite approach embeds the strain buffering function within the device stack itself, avoiding the need for separate strain relief mechanisms and minimizing additional complexity while significantly improving film quality.
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 reduces defect density and improves crystal quality of α-Ga2O3 epitaxial films, avoiding the contradictory epitaxial temperature issues and enabling the production of high-quality gallium oxide films suitable for semiconductor power and photoelectronic devices.
Implementation Method 1
A pulsed epitaxial growth method is employed to form α-(AlxGa1-x)2O3 strain buffering layers on sapphire substrates
Implementation Method 2
common preparation methods of α-Ga2O3 materials include various chemical vapor deposition (CVD) processes
Data Source
AI summary
The disclosure provides a gallium oxide film based on sapphire substrate as well as a growth method and an application thereof. The gallium oxide film based on sapphire substrate is prepared by a method below, including: forming more than one α-(AlxGa1-x)2O3 strain buffering layers on the sapphire substrate by means of pulsed epitaxial growth, wherein 0.99≥x≥0.01; and forming gallium oxide epitaxial layers on the α-(AlxGa1-x)2O3 strain buffering layers. The growth method provided can not only avoid the technical difficulty of contradictory epitaxial temperatures of α-Ga2O3 and α-Al2O3, but also effectively reduce the defect density of α-Ga2O3 epitaxial film, thus further improving the crystal quality of the α-Ga2O3 epitaxial film materials.