Trench-Gate MISFET Layout for Higher Current Capacity
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Solution Overview
Problem
Existing semiconductor devices with common source/drain type MISFETs face challenges in enhancing electric current capacity due to limitations in current path efficiency.
Innovation Solution
The semiconductor device incorporates a semiconductor chip with a drift layer, trench gate structure, channel region, and source/drain regions formed along the side wall of the trench gate structure, increasing the current path and improving electric current capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conventional common source/drain type MISFET structure is used, then the device structure is simple and easy to manufacture, but the electric current capacity is limited
Solution Approach 1:
The patent transitions from a planar current path to a three-dimensional current path by forming source/drain regions along the side wall of the trench gate structure. This vertical integration along the trench sidewalls creates additional current conduction paths in the depth dimension, thereby increasing the effective current capacity without significantly increasing the planar footprint or manufacturing complexity
2Quantity of substance
If the current path is increased to improve electric current capacity, then the electric current capacity improves, but the leakage current may increase
Solution Approach 1:
The patent applies different conductivity types to different regions: the drift layer has first conductivity type while the channel region has second conductivity type. This local differentiation creates effective pn junctions that provide electrical isolation, allowing the current path to be extended along the trench side wall while preventing leakage current through the channel region
Data Source
AI summary
A semiconductor device includes a semiconductor chip having a main surface, a first conductivity type drift layer formed in a surface layer portion of the main surface, a trench gate structure formed in the main surface such as to be in contact with the drift layer, a second conductivity type channel region formed in the drift layer such as to cover a side wall of the trench gate structure, and first and second source/drain regions formed at intervals in a region along the side wall of the trench gate structure in the drift layer such as to oppose each other across the channel region.