Semiconductor Terminal Structure for Dynamic Avalanche Suppression
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Solution Overview
Problem
Existing semiconductor devices, such as ultra-fast diodes, MOSFETs, and IGBTs, suffer from dynamic avalanche breakdown when turned off at high speed and high DC voltage, leading to uneven current and electric field distributions, current concentration, and potential device burnout.
Innovation Solution
A semiconductor device with an active area and a terminal area, featuring a semiconductor substrate with a base region and annular subregions of opposite conductivity type, an insulating layer with openings, and a conductive layer that extends across the junction between the active and terminal areas, ensuring uniform electric field and current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ultra-fast diode is turned off at high speed and high DC voltage, then the switching performance is improved, but dynamic avalanche breakdown occurs leading to current concentration and device burnout
Solution Approach 1:
The patent introduces a base region with graded doping concentration in the terminal area, creating local variations in electrical properties. The doping concentration decreases from the bottom toward the top of the base region, which locally modifies the electric field distribution to prevent concentration effects during high-speed switching
Solution Approach 2:
The base region acts as an intermediary structure between the pn junction and the terminal contact. This intermediate region with its specific doping profile mediates the electric field distribution, preventing direct field concentration at the pn junction during avalanche breakdown
2Device complexity
If conventional structure is used, then the device structure is simple, but current and electric field distribution are uneven causing current filaments at pn junctions
Solution Approach 1:
The patent modifies only the terminal area with a base region having graded doping, while keeping the active area structure conventional. This localized modification improves current distribution uniformity without substantially increasing overall device complexity
Data Source
AI summary
A semiconductor device has an active area and a terminal area surrounding the active area and includes a base region, a plurality of annular subregions, an insulating layer provided with a plurality of insulating layer openings, and a first conductive layer. The plurality of annular subregions includes a first annular subregion in contact with the base region. The first annular subregion includes a plurality of annular structures in contact with each other. All the annular structures contact the first conductive layer through the corresponding insulating layer openings. The base region, the annular subregions, and the annular structures have a second conductivity type.