SiC Trench Gate Insulating Film Breakdown Prevention
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Solution Overview
Problem
Semiconductor devices with trench gate structures using silicon carbide face premature breakdown of the gate insulating film and gate electrode due to high electric field strengths, which is not effectively addressed by existing technologies.
Innovation Solution
The semiconductor device incorporates a gate electrode structure where the corner portions extend inwardly and are inset into the base regions, with a specific dopant concentration profile and insulating films to reduce electric field intensity on the gate insulating film, preventing breakdown and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If silicon carbide is used as the semiconductor material to increase electric field strength, then the breakdown voltage and current carrying capacity are improved, but the gate insulating film and gate electrode break down prematurely due to excessive electric field intensity
Solution Approach 1:
The patent applies different dopant concentrations to different regions: higher concentration in the accumulation region near the gate electrode to suppress electric field intensity, and lower concentration in the drift region to maintain high breakdown voltage. This local differentiation resolves the contradiction by protecting the gate area while preserving the high power capability of silicon carbide
Solution Approach 2:
The patent changes the dopant concentration parameter spatially within the semiconductor structure. By creating a non-uniform dopant distribution with peak concentration near the gate and decreasing concentration toward the drain, the electric field profile is modified to prevent gate breakdown while maintaining high voltage blocking capability
2Productivity
If trench gate structure is used to increase channel density, then current carrying capacity is improved, but electric field concentration on the gate insulating film increases causing breakdown
Solution Approach 1:
The patent creates a localized high-dopant region at the accumulation zone directly beneath the gate electrode corners, which specifically addresses the electric field concentration problem at these critical points while maintaining the trench gate structure's high channel density advantage
Solution Approach 2:
The patent preemptively introduces a high-concentration dopant region before device operation to counteract the electric field concentration that would otherwise occur at the gate electrode corners. This preliminary structural modification prevents the harmful effect before it can cause breakdown
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 design effectively suppresses electric field concentration on the gate insulating film, preventing breakdown and improving the reliability of the semiconductor device by optimizing the dopant concentration and structural geometry.
Implementation Method 1
The electric field intensity of silicon carbide at breakdown is about ten times as large as that of silicon
Implementation Method 2
a specific dopant concentration profile and insulating films to reduce electric field intensity on the gate insulating film
Data Source
AI summary
A semiconductor device includes a first electrode, a second electrode, a first semiconductor region of a first conductivity type between the first electrode and the second electrode, a plurality of second semiconductor regions of a second conductivity type selectively provided between the first semiconductor region and the second electrode, a third semiconductor region of the first conductivity type provided between each of the second semiconductor regions and the second electrode, an insulating film provided on the first semiconductor region in a location between adjacent second semiconductor regions, the second semiconductor regions, and the third semiconductor region; and a third electrode located over the insulating film, wherein a portion of the insulating film and the third electrode extend inwardly of the second semiconductor regions.