Semiconductor Device Field Plate Electrode Trench Design
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Solution Overview
Problem
The existing trench-based field plate electrode structures in power MOSFETs improve withstand voltage in the element region but are prone to gate line destruction due to electric field crowding in the terminal region under reverse bias.
Innovation Solution
A semiconductor device design featuring a dot pattern arrangement of first field plate electrodes in the element region and a stripe pattern of second field plate electrodes in the terminal region, with specific trench and insulation film configurations to alleviate electric field concentration and enhance symmetric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trench-based field plate electrode structures are used to improve withstand voltage in the element region, then withstand voltage is improved, but gate lines in the terminal region are destroyed due to electric field crowding under reverse bias
Solution Approach 1:
The field plate electrode structure is segmented into two distinct patterns: dot-pattern field plate electrodes in the element region and stripe-pattern field plate electrodes in the terminal region. This segmentation allows each region to have an optimized structure for its specific requirements, resolving the contradiction between withstand voltage improvement and electric field crowding prevention
Solution Approach 2:
Different structural qualities are applied to different regions: the element region uses dot-pattern field plate electrodes for withstand voltage enhancement, while the terminal region uses stripe-pattern field plate electrodes to reduce electric field crowding and protect gate lines. This local differentiation resolves the contradiction by tailoring the structure to regional needs
2Reliability
If dot pattern field plate electrodes are used in the element region, then withstand voltage is improved and ineffective area is reduced, but electric field concentration occurs in the terminal region
Solution Approach 1:
The patent segments the field plate electrode configuration into dot-pattern for the element region and stripe-pattern for the terminal region. This segmentation allows the dot pattern to maximize withstand voltage in the element region while the stripe pattern mitigates electric field concentration in the terminal region
Solution Approach 2:
The invention applies different local qualities: dot-pattern field plate electrodes with specific spacing in the element region to enhance withstand voltage, and stripe-pattern field plate electrodes in the terminal region to distribute and reduce electric field concentration, thus resolving the contradiction between these two opposing effects
Data Source
AI summary
A semiconductor device of an embodiment includes: a first semiconductor layer of a first conductive type; a second semiconductor layer of the first conductive type, being provided on the first semiconductor layer and including a first trench, a plurality of holes, a plurality of second trenches, and a plurality of third trenches; a first semiconductor region of a second conductive type, being provided on the second semiconductor layer; a second semiconductor region of the first conductive type, being provided on the first semiconductor region; a first electrode electrically connected to the second semiconductor region; a second electrode disposed in the first trench via a first insulation film; a plurality of first field plate electrodes having a column shape, being electrically connected to the first electrode, interposing the second electrode, and being disposed in the holes via a second insulation film; a plurality of third electrodes extending from ends of the first insulation films in a first direction to the first direction, being disposed in the second trenches via third insulation films and extending from ends of the second electrodes in the 1st direction to the first direction; a plurality of second field plate electrodes extending in the first direction, being apart from the first field plate electrodes, being disposed in the third trenches via fourth insulation films, being electrically connected to the first field plate electrode via the first electrode, and interposing the third electrode; and a fourth electrode electrically connecting the second electrode and the third electrode.