Metal Strapping Guard Ring Trenches Shrink Termination Area
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Solution Overview
Problem
Conventional semiconductor power devices face challenges in reducing on-state resistance (RdsA) while maintaining high breakdown voltage, with existing configurations and manufacturing methods either increasing RdsA or requiring complex fabrication processes.
Innovation Solution
A semiconductor power device configuration with a metal strapping configuration in the termination area, where two or more adjacent trenches are shorted to P-body regions creating electric dead zones, reducing the termination area without compromising breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional termination structures are used to maintain high breakdown voltage, then the breakdown voltage is maintained, but the termination area becomes larger
Solution Approach 1:
The termination region is segmented into multiple zones with different doping concentrations and trench configurations. The first termination zone has a different doping profile than the second termination zone, allowing each zone to be optimized for its specific function. This segmentation enables more efficient use of the termination area while maintaining the required breakdown voltage through progressive voltage grading across the zones.
Solution Approach 2:
The patent introduces vertical dimensionality through deep trenches that extend through the drift region and into the substrate. These trenches create three-dimensional field management structures that allow voltage grading in both horizontal and vertical directions. The trenches with conductive fillings create equipotential surfaces that help distribute the electric field more efficiently, reducing the horizontal area needed for termination while maintaining breakdown voltage.
Data Source
AI summary
This invention discloses a semiconductor power device formed in a semiconductor substrate of a first conductivity type comprises an active cell area and a termination area surrounding the active cell area and disposed near edges of the semiconductor substrate. The termination area includes a plurality of trenches filled with a conductivity material forming a shield electrode and insulated by a dielectric layer along trench sidewalls and trench bottom surface wherein the trenches extending vertically through a body region of a second conductivity type near a top surface of the semiconductor substrate and further extending through a surface shield region of the first conductivity type. A dopant region of the second conductivity type disposed below the surface shield region extending across and surrounding a trench bottom portion of the trenches. At least a metal connector disposed above the top surface of the semiconductor substrates electrically connecting to the shield electrode of at least two trenches and shorted to the body region.