SiC Substrate Periodic Texture for Dislocation Reduction
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Solution Overview
Problem
Conventional methods for reducing basal plane dislocations in SiC substrates before epitaxial growth either suppress step growth, leading to low-quality crystals, or involve alkali contamination and significant thickness variations that reduce the effectiveness of SiC semiconductor devices.
Innovation Solution
A periodic texture is formed on the SiC substrate with an angle between the basal plane and the texture surface smaller than the off angle, reducing basal plane dislocation density and stacking faults by inhibiting the propagation of basal plane dislocations to the epitaxial layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to reduce basal plane dislocations before epitaxial growth, then dislocation density is reduced, but step growth is suppressed leading to low-quality crystals
Solution Approach 1:
The invention changes the surface orientation parameter by forming a texture surface with a specific angle relationship to the basal plane. By controlling the angle between the texture surface and basal plane to be smaller than the off angle, the invention modifies the growth parameters to allow step growth to continue while reducing basal plane dislocation propagation, thus resolving the contradiction between dislocation reduction and crystal quality maintenance
2Manufacturing precision
If alkali treatment is applied to reduce dislocations, then dislocation density decreases, but alkali contamination and thickness variations occur that reduce device effectiveness
Solution Approach 1:
The invention replaces the chemical alkali treatment method with a physical texture formation method. By forming a periodic texture on the substrate surface through controlled processes, the invention achieves dislocation reduction without introducing alkali contamination or significant thickness variations, thus eliminating the harmful side effects while maintaining the beneficial dislocation reduction effect
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 effectively reduces the number of stacking faults and prevents a decrease in forward current over time under constant voltage, enabling the production of high-quality SiC semiconductor devices with improved reliability and mass productivity.
Implementation Method 1
epitaxial growth of an epitaxial film on an SiC substrate
Data Source
AI summary
A semiconductor device is provided in which a front surface of an SiC substrate is treated before epitaxial growth so as to reduce crystal defects such as stacking faults. In an aspect, an epitaxial layer is deposited on an SiC substrate in which a periodic texture is formed in a direction perpendicular to a <−1100> direction of the SiC substrate and in which an angle between a basal plane of the SiC substrate and a surface of the formed texture is smaller than an off angle.