SiC Power Semiconductor Oxide Interface Using Low-Energy Electron Irradiation
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Solution Overview
Problem
Existing power semiconductor devices using silicon carbide (SiC) face high on-state resistance due to a large density of interface states at the SiO2/SiC interface, primarily attributed to carbon-related defects, which reduce charge carrier mobility and cause a shift in flat-band voltage.
Innovation Solution
Employing low-energy electron radiation with a kinetic energy between 116 keV and 210 keV to displace carbon atoms from the SiC surface, creating a carbon-poor layer that acts as a sink for injected carbon, thereby reducing interface states and improving electronic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional oxidation methods are used to form SiO2/SiC interface, then electrical insulation layer is formed, but carbon-related defects are introduced at the interface causing high on-state resistance
Solution Approach 1:
The patent applies preliminary low-energy electron irradiation to the SiC substrate before oxidation to create a carbon-poor layer. This preliminary action modifies the substrate structure in advance, preventing carbon-related defects from forming at the SiO2/SiC interface during subsequent oxidation, thereby reducing interface states density and improving on-state resistance
Solution Approach 2:
The patent converts the harmful effect of carbon atoms (which normally create defects during oxidation) into a beneficial outcome by using low-energy electron irradiation to selectively remove carbon atoms from the surface layer. This creates a carbon-poor layer that actually protects against carbon-related defects, transforming the potential harm of carbon presence into a benefit of reduced interface states
2Object-generated harmful factors
If low-energy electron radiation is applied to remove carbon atoms, then interface states are reduced, but additional processing steps are required
Solution Approach 1:
The patent changes the energy parameter of electron radiation to a specific low-energy range (10-100 keV) that selectively affects carbon atoms without damaging the SiC crystal structure or requiring additional processing steps. This parameter optimization allows the carbon removal to be integrated into existing manufacturing workflows while achieving the desired reduction in interface states
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 method effectively reduces interface states, enhances charge carrier mobility, and stabilizes flat-band voltage without introducing additional impurities or defects, resulting in improved on-state resistance and operational characteristics.
Implementation Method 1
irradiating at least one first portion of a top side of the semiconductor body with low-energy electron radiation, wherein by means of the low-energy electron radiation in the at least one first portion carbon atoms are moved from the top side into the semiconductor body
Data Source
AI summary
A method for producing a power semiconductor device comprises providing a semiconductor body based on SiC, irradiating at least a first portion of a top side of the semiconductor body with low-energy electron radiation, and producing an electrical insulation layer at least in the at least one irradiated first portion.