Cross-Trench Power Semiconductor Switch for dV/dt Control
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Solution Overview
Problem
Power semiconductor devices face challenges in minimizing switching losses and controlling voltage and current slopes (dV/dt and dl/dt) effectively, particularly in high-power applications where trench configurations and electrode connections impact device performance.
Innovation Solution
The power semiconductor device incorporates a design with multiple trenches and mesas, including control and dummy trenches, and a decoupling structure within mesas to separate active and termination regions, allowing for precise control of load current and voltage slopes, thereby optimizing switching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single trench configuration is used, then the device structure is simple, but switching losses increase and dV/dt control becomes difficult
Solution Approach 1:
The device divides the active region into multiple independent power cells, each with its own trenches and mesas. This segmentation allows independent control of switching processes in different regions, enabling reduced switching losses through optimized turn-on and turn-off sequences while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
Different trenches within the same power cell are assigned different electrode connections (control terminal vs. load terminal). This creates local quality variations where first trenches provide dV/dt control while second trenches support current conduction, allowing simultaneous optimization of switching performance and structural organization.
2Reliability
If multiple trenches with different electrode connections are used, then dV/dt controllability improves, but device structure becomes more complex
Solution Approach 1:
The trench structure serves multiple functions simultaneously: first trenches provide dV/dt control through control terminal connection, while second trenches provide current conduction paths. This multi-functionality approach improves reliability by enabling precise voltage slope control without proportionally increasing structural complexity, as the same basic trench geometry is reused with different electrical connections.
Solution Approach 2:
Trenches connected to the same terminal are maintained at the same electrical potential, creating equipotential regions. This principle simplifies the complex multi-trench structure by grouping trenches with identical connections, reducing the number of unique structural configurations needed while maintaining precise dV/dt controllability through controlled potential differences between terminal groups.
3Loss of energy
If switching duration is reduced to minimize switching losses, then energy efficiency improves, but control over voltage and current slopes becomes more difficult
Solution Approach 1:
The device prepares multiple trenches with different electrode connections in advance, so that during switching operations, the desired dV/dt control and current conduction paths are already in place. This preliminary configuration allows rapid switching with reduced duration while maintaining ease of control over voltage and current slopes, as the control structure is pre-established rather than dynamically created during switching.
Data Source
AI summary
A power semiconductor switch includes an active cell region with a drift region, an edge termination region, and IGBT cells within the active cell region. Each IGBT cell includes trenches that extend into the drift region and laterally confine mesas. At least one control trench has a control electrode for controlling the load current. At least one dummy trench has a dummy electrode electrically coupled to the control electrode. At least one further trench has a further trench electrode. At least one active mesa is electrically connected to a first load terminal within the active cell region. Each control trench is arranged adjacent to no more than one active mesa. At least one inactive mesa is adjacent to the dummy trench. A cross-trench structure merges each control trench, dummy trench and further trench to each other. The cross-trench structure overlaps at least partially along a vertical direction with the trenches.