Semiconductor Diode Layout for Reverse Recovery Overshoot Suppression
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Solution Overview
Problem
Semiconductor devices, such as IGBTs, face challenges in suppressing voltage overshoot during reverse recovery, which affects their performance and reliability.
Innovation Solution
The semiconductor device incorporates a specific arrangement of conductivity-type regions, including first and second cathode regions and floating regions, on a semiconductor substrate to optimize the reverse recovery process, with the floating regions overlapping the cathode regions to reduce voltage overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diode structure is used, then device simplicity is maintained, but voltage overshoot during reverse recovery cannot be suppressed
Solution Approach 1:
The diode cathode is segmented into multiple cathode regions (first cathode regions and second cathode regions) with different conductivity types, arranged in a specific pattern. This segmentation allows different regions to perform different functions during reverse recovery, suppressing voltage overshoot while maintaining manageable structural complexity
Solution Approach 2:
Different cathode regions are assigned different conductivity types (first conductivity type and second conductivity type) to create local quality variations. The floating regions are strategically positioned to overlap specific cathode regions, creating localized electrical characteristics that suppress voltage overshoot during reverse recovery
2Reliability
If floating regions are added to suppress voltage overshoot, then reverse recovery characteristics improve, but manufacturing complexity increases
Solution Approach 1:
The floating regions are positioned in a specific dimensional arrangement that overlaps the cathode regions when viewed from above the semiconductor substrate. This spatial arrangement in the planar dimension simplifies the formation process compared to three-dimensional structures, while still achieving the desired reverse recovery characteristics
Data Source
AI summary
A semiconductor device, including a semiconductor substrate, a transistor section and a diode section arranged in a predetermined arrangement direction and provided on the semiconductor substrate, is provided. The diode section includes a drift region of a first conductivity-type provided in the semiconductor substrate, a base region of a second conductivity-type extending to a height of an upper surface of the semiconductor substrate and provided above the drift region, first cathode regions of the first conductivity-type, and second and third cathode regions of the second conductivity-type. The first, second, and third cathode regions extend to a height of a lower surface of the semiconductor substrate in a depth direction and provided below the drift region. The first and second cathode regions are provided in contact with each other, alternating in the arrangement direction, and sandwiched between the third cathode regions in an extension direction orthogonal to the arrangement direction.