SiC Power Device Recess Gate Insulating Layer
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Solution Overview
Problem
Power semiconductor devices using silicon carbide (SiC) face challenges in electric field concentration and channel resistance, which affect their performance in high-voltage and high-temperature applications.
Innovation Solution
The design includes a semiconductor layer with a vertical drift region, well regions, recess gate electrodes, source regions, and insulating-layer protective regions to mitigate electric field concentration and reduce channel resistance, while increasing channel density through a multi-lateral channel structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a trench type of gate structure is used to increase channel density, then channel density is improved, but electric field concentration occurs at the trench corner
Solution Approach 1:
The patent applies local quality by introducing a protective region with a second conductive type at the trench corner where electric field concentration occurs. This localized modification changes the electrical properties specifically at the problematic corner region without altering the overall trench gate structure, thereby maintaining high channel density while mitigating electric field concentration.
Solution Approach 2:
The protective region acts as an intermediary element between the drift region and the gate structure. By introducing this intermediate region with opposite conductive type, the patent mediates the electric field distribution, preventing direct concentration at the trench corner while preserving the benefits of the trench gate structure for increasing channel density.
2Ease of manufacture
If conventional silicon is used, then manufacturing is easier, but breakdown voltage and heat dissipation are insufficient for high-power applications
Solution Approach 1:
The patent changes the fundamental material parameter from silicon to silicon carbide, which has inherently superior electrical and thermal properties. This parameter change enables the device to achieve higher breakdown voltage and better heat dissipation capability, making it suitable for high-power applications despite the increased manufacturing complexity.
Solution Approach 2:
The patent employs silicon carbide, a composite material with unique properties that combine the benefits of wide bandgap semiconductor characteristics with practical device fabrication. This material choice enables simultaneous achievement of high breakdown voltage, excellent heat dissipation, and functional device performance.
Data Source
AI summary
A power semiconductor device includes a semiconductor layer based on silicon carbide (SiC), a vertical drift region positioned to extend in a vertical direction inside the semiconductor layer and having a first conductive type, a well region positioned in at least one side of the vertical drift region to make contact with the vertical drift region and having a second conductive type, recess gate electrodes extending from a surface of the semiconductor layer into the semiconductor layer and buried in the vertical drift region and the well region to cross the vertical drift region and the well region in a first direction, source regions positioned in the well region between the recess gate electrodes and having the first conductive type, and insulating-layer protective regions surrounding lower portions of the recess gate electrodes, respectively, in the vertical drift region, and having the second conductive type.