SiC Device Poly-Silicon Hydrogen Blocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high interface state density at the SiO2/SiC interface in silicon carbide semiconductor devices leads to increased ON resistance and conduction loss, which is not effectively addressed by existing methods, particularly under high-temperature and high-voltage conditions.
Innovation Solution
A silicon carbide semiconductor device with a poly-silicon film of specific thickness, combined with titanium and titanium nitride films, is used to absorb and block hydrogen ions generated from the source electrode, preventing them from reaching the gate insulating film and reducing the variation of the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal oxidation is performed in an atmosphere including nitrous oxide or nitric oxide to reduce interface state density, then channel mobility is improved and ON resistance is reduced, but the device complexity increases due to additional process requirements
Solution Approach 1:
The patent changes the oxidation atmosphere composition by introducing nitrogen-containing gases (nitrous oxide or nitric oxide) to modify the oxidation process. This parameter change reduces interface state density at the SiO2/SiC interface, thereby improving channel mobility and reducing ON resistance while maintaining device performance
Solution Approach 2:
The patent creates a composite gate insulating film structure by forming silicon dioxide through thermal oxidation in a nitrogen-containing atmosphere. The resulting film has reduced interface state density compared to conventional oxidation, effectively creating a higher-quality insulating layer that improves device reliability
2Ease of manufacture
If a gate insulating film is formed by thermal oxidation on a silicon carbide semiconductor substrate, then the MOS gate structure is established, but interface state density increases leading to increased ON resistance and conduction loss
Solution Approach 1:
The patent modifies the thermal oxidation process by changing the atmosphere composition to include nitrogen-containing gases. This parameter change transforms the oxidation process to produce a gate insulating film with reduced interface state density, thereby reducing ON resistance and conduction loss while maintaining ease of manufacture through standard thermal oxidation equipment
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 configuration stabilizes the threshold voltage and improves the reliability of silicon carbide semiconductor devices by suppressing the generation of positive charge at the gate insulating film interface, even under negative voltage application, thereby enhancing the device's electrical characteristics and operational stability.
Implementation Method 1
thermally oxidizing a silicon carbide semiconductor portion and forming a silicon dioxide film on a surface of the silicon carbide semiconductor portion
Implementation Method 2
an alloy layer is formed by causing the second titanium film and the first main electrode to react
Data Source
AI summary
A silicon carbide semiconductor device, including a silicon carbide semiconductor structure, an insulated gate structure, an interlayer insulating film formed on the insulated gate structure, a poly-silicon film formed on the interlayer insulating film, and a main electrode formed on the poly-silicon film and in electrical connection with the silicon carbide semiconductor structure. The insulated gate structure includes a gate insulating film, which is a silicon dioxide film contacting the silicon carbide semiconductor structure, and a gate electrode formed on the gate insulating film.