Power Semiconductor Trench Layout for Compact Current Sensing
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Solution Overview
Problem
Existing power semiconductor integrated circuits (ICs) face challenges in reducing chip area while maintaining high reliability and efficiency, particularly in integrating output-stage and detection elements for current sensing, which requires separate channel-formation regions and terminal structures to ensure breakdown voltage and area efficiency.
Innovation Solution
A semiconductor device configuration where the output-stage and detection elements share common first trenches extending in parallel, with additional second trenches perpendicular to them, separating their channel-formation regions, and utilizing buried gate electrodes and electric field relaxation regions to optimize area usage and electrical separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the detection element is buried in the output-stage element to share common structures, then the chip area is reduced, but separate terminal structures are required to ensure breakdown voltage which reduces area efficiency
Solution Approach 1:
The patent merges the terminal structures of the detection element and output-stage element into a single shared terminal structure. The common drain region serves as a shared terminal for both elements, eliminating the need for separate terminal structures and reducing chip area while maintaining electrical isolation through the shallow trench insulating films between the channel-formation regions.
2Reliability
If separate channel-formation regions are provided for detection and output-stage elements, then breakdown voltage is ensured, but chip area increases
Solution Approach 1:
The patent segments the channel-formation regions of the detection element and output-stage element using shallow trench insulating films. These insulating films create physical separation between the channel-formation regions, ensuring electrical isolation and maintaining breakdown voltage while allowing the elements to share common structures and reduce overall chip area.
3Reliability
If the detection element is arranged separately from the output-stage element, then channel separation is achieved, but metal wiring area increases
Solution Approach 1:
The patent merges the gate structures of the detection element and output-stage element into a single common gate. The gate electrode extends continuously over both elements, eliminating the need for separate metal wiring to connect individual gates. This reduces metal wiring area while maintaining proper channel separation through the shallow trench insulating films.
Data Source
AI summary
A semiconductor device includes an output-stage element and a detection element, each of the output-stage element and the detection element including: a channel-formation region deposited at an upper part of a drift region; a main electrode region deposited at an upper part of the channel-formation region; and a gate electrode buried via a gate insulating film in one or more first trenches in contact with the main electrode region, the channel-formation region, and the drift region, wherein the first trenches used in common with the detection element and the output-stage element extend in a planar pattern, and a plurality of second trenches extending in parallel to each other in a direction perpendicular to the first trenches interpose the detection element so as to separate the channel-formation region of the output-stage element and the channel-formation region of the detection element from each other.