Vertical MOSFET Trench Gate Segmentation for Termination Voltage
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Solution Overview
Problem
Semiconductor devices with a super junction structure face challenges in maintaining high withstand voltage and low on-resistance, particularly in the termination region where the withstand voltage is lower compared to the cell region.
Innovation Solution
The configuration involves providing two or more trench gates between adjacent p-type column regions in the cell portion, which extend to the termination portion and connect to a single connection trench gate, along with different p-type column regions in the termination portion, reducing on-resistance and enhancing withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two or more trench gates are provided between adjacent p type column regions, then on-resistance is reduced, but withstand voltage in the termination portion is lowered
Solution Approach 1:
The device is divided into two distinct regions: a cell portion with multiple trench gates between p-type column regions to reduce on-resistance, and a termination portion with a connection trench gate to maintain withstand voltage. This spatial segmentation allows each region to be optimized for its specific function without compromising the other.
Solution Approach 2:
Different gate configurations are applied to different regions of the device. The cell portion uses multiple trench gates (first trench gates) optimized for low on-resistance, while the termination portion uses a single connection trench gate (second trench gate) optimized for high withstand voltage. Each region has locally optimized properties suited to its functional requirements.
2Device complexity
If the trench gate extends from the cell region to the termination region, then manufacturing complexity is reduced, but the withstand voltage distribution becomes non-uniform
Solution Approach 1:
The continuous trench gate structure is segmented into two functional portions: first trench gates in the cell region and a second trench gate (connection trench gate) in the termination region. This segmentation allows the gate to extend continuously from cell to termination region (reducing manufacturing complexity) while maintaining different electrical characteristics in each region (preserving withstand voltage uniformity).
Data Source
AI summary
A semiconductor device according to an embodiment comprises: a cell portion in which a vertical type MOSFET is formed; and a termination portion arranged adjacent to the cell portion. The termination portion includes a connection trench gate provided along a first direction. The cell portion includes: a plurality of first column regions provided along a second direction intersecting the first direction; and a plurality of trench gates provided along the second direction such that two trench gates are arranged between the two adjacent first column regions. The plurality of trench gates extend from the cell portion to the termination portion and are connected to the connection trench gate. The plurality of first column regions extend from the cell portion to the termination portion, and the termination portion includes a plurality of second column regions different from the plurality of first column regions.