SiC Trench MOSFET Source Doping for Low On-Resistance Blocking
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Solution Overview
Problem
Silicon carbide semiconductor devices face a trade-off between reducing area-specific on-state resistance and maintaining blocking voltage capability, where improving one characteristic often deteriorates the other, necessitating a design that balances multiple device specifications.
Innovation Solution
The semiconductor device features a silicon carbide body with a source region and body region of different conductivity types, including a trench structure with a gate electrode and gate dielectric, and a source region with specific doping concentration profiles and sub-regions to optimize bulk resistance and reduce effective gate overvoltage, achieved through precise doping concentration profiles and sub-region arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drift zone doping concentration is increased to improve area-specific on-state resistance, then on-state resistance decreases, but blocking voltage capability deteriorates
Solution Approach 1:
The source region is divided into multiple source sub-regions with different doping concentrations, allowing different portions to contribute differently to conduction and blocking functions
Solution Approach 2:
Different source sub-regions are assigned different doping concentrations to perform different local functions: higher doping in contact-adjoining regions for low resistance, lower doping in gate-overlapping regions for voltage blocking
Data Source
AI summary
A semiconductor device includes: a silicon carbide semiconductor body having a source region of a first conductivity type and a body region of a second conductivity type; and a trench structure extending from a first surface into the silicon carbide semiconductor body along a vertical direction, the trench structure having a gate electrode and a gate dielectric. The trench structure is stripe-shaped and runs along a longitudinal direction that is perpendicular to the vertical direction. The source region includes a first source sub-region and a second source sub-region alternately arranged along the longitudinal direction. A doping concentration profile of the first source sub-region along the vertical direction differs from a doping concentration profile of the second source sub-region along the vertical direction. A corresponding method of manufacturing the semiconductor device is also described.