Power Semiconductor Switch Cross-Trench Structure
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Solution Overview
Problem
Existing power semiconductor switches face challenges in achieving low switching losses and precise control over switching operations, particularly in managing voltage and current slopes during switching, which affects their efficiency in applications like power converters and electric motors.
Innovation Solution
A power semiconductor switch design featuring a configuration with multiple trenches and mesas, including control, dummy, and further trenches, along with a cross-trench structure, to enhance control over load current and voltage, and a method for processing these switches to optimize dopant concentration profiles for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power semiconductor switch designs are used, then manufacturing is simpler, but switching losses increase and control precision deteriorates
Solution Approach 1:
The power semiconductor switch is divided into multiple IGBT cells, each containing segmented trenches (control trench, dummy trench, further trench) and mesas. This segmentation allows independent optimization of switching control in each cell while distributing the overall switching losses across multiple units, thereby reducing total energy loss during switching operations.
Solution Approach 2:
Different regions of the device are given different properties: the control trench contains a control electrode for precise voltage control, the dummy trench has a dummy electrode for current balancing, and the further trench provides additional control. Each mesa region is optimized for specific functions such as current conduction or voltage blocking, achieving low switching losses through localized functional optimization.
2Measurement precision
If simple trench configurations are used, then device complexity is reduced, but control precision over load current and voltage deteriorates
Solution Approach 1:
The multiple electrode configurations (control electrode in control trench, dummy electrode in dummy trench, and further electrode in further trench) create feedback mechanisms that monitor and adjust voltage and current distribution across the IGBT cells. This feedback enables precise control of switching operations by detecting voltage slopes (dV/dt) and current slopes (dl/dt) and adjusting gate signals accordingly.
Solution Approach 2:
The trench and electrode structure serves multiple functions simultaneously: the control trench provides primary switching control, the dummy trench balances current distribution and reduces voltage imbalance, and the further trench provides additional control or protection functions. This multi-functionality achieves high control precision without requiring separate dedicated structures for each function.
3Ease of operation
If switching duration is extended to improve control, then control precision improves, but switching losses increase
Solution Approach 1:
The switching control is implemented through periodic gate voltage pulses applied to the control electrode. By using short, precisely-timed periodic pulses rather than extended continuous control, the device achieves precise switching control while minimizing the duration of high-loss transition states. The periodic nature allows for optimized turn-on and turn-off sequences that reduce overall switching losses.
Solution Approach 2:
The control system dynamically adjusts the switching characteristics by varying gate voltage levels and timing based on real-time operating conditions. The multiple electrode configuration allows dynamic balancing of voltage and current distribution during switching transitions, enabling precise control with minimized transition durations and consequently reduced switching losses.
Data Source
AI summary
A power semiconductor switch includes a cross-trench structure associated with at least one IGBT cell. The cross-trench structure merge at least one control trench, at least one dummy trench and at least one further trench of at least one IGBT cell to each other. The cross-trench structure overlaps at least partially along a vertical direction with trenches of the at least one IGBT-cell.