SiC Single Crystal Doping for Stacking Fault Reduction
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Solution Overview
Problem
Existing methods for manufacturing silicon carbide (SiC) single crystals with low resistance tend to generate high stacking faults when nitrogen is doped at concentrations above 2×10^19 cm^-3, leading to increased leakage and negative effects on device electric characteristics.
Innovation Solution
Concurrent doping of nitrogen and aluminum in SiC single crystals, with a nitrogen concentration of 2×10^19 cm^-3 or higher and an aluminum to nitrogen (Al/N) ratio within 5% to 40%, to reduce specific resistance and stacking faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrogen is doped at high concentration (2×10^19 cm^-3 or higher) to reduce specific resistance, then electrical conductivity is improved, but stacking faults increase substantially
Solution Approach 1:
Oxygen acts as an intermediary element that suppresses stacking fault generation during nitrogen doping. By introducing oxygen at a concentration of 1×10^19 cm^-3 or higher, the harmful effect of nitrogen doping (stacking faults) is mitigated while maintaining the desired electrical conductivity improvement
Solution Approach 2:
The invention changes the compositional parameters by controlling the concentration ratio between nitrogen and oxygen. By maintaining nitrogen concentration at 2×10^19 cm^-3 or higher while simultaneously maintaining oxygen concentration at 1×10^19 cm^-3 or higher, the system achieves low specific resistance without excessive stacking faults
2Reliability
If nitrogen doping concentration is increased to achieve lower specific resistance, then device resistance decreases, but stacking faults become a leak current source causing negative effects on electric characteristics
Solution Approach 1:
Oxygen serves as a protective intermediary that prevents nitrogen-induced stacking faults from becoming leak current sources. The oxygen atoms interact with the crystal structure to stabilize regions that would otherwise form defect sites, thereby maintaining low specific resistance without creating leakage pathways
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 stacking faults by up to 95% and achieves specific resistances suitable for devices, minimizing negative effects on electric characteristics while maintaining low resistance.
Implementation Method 1
Concurrent doping of nitrogen and aluminum in SiC single crystals, with a nitrogen concentration of 2×10^19 cm^-3 or higher and an aluminum to nitrogen (Al/N) ratio within 5% to 40%
Data Source
AI summary
A silicon carbide single crystal includes nitrogen as a dopant and aluminum as a dopant. A nitrogen concentration is 2×1019 cm−3 or higher and a ratio of an aluminum concentration to the nitrogen concentration is within a range of 5% to 40%.