IGBT Auxiliary Mesa dV/dt Control Trench Structure
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Solution Overview
Problem
Power semiconductor devices face challenges in minimizing switching losses and achieving precise control over voltage and current slopes, particularly in applications requiring high voltage and current handling, where existing designs struggle to optimize dV/dt and dl/dt characteristics.
Innovation Solution
The design incorporates a power semiconductor device with an IGBT configuration featuring multiple trenches and mesas, including an auxiliary mesa, which is laterally confined by a source trench and a control trench, allowing for improved control over the load current and voltage slope by utilizing semiconductor portions of specific conductivity types and dopant concentrations to manage the switching behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If short switching durations are used to reduce switching losses, then switching losses are reduced, but control over voltage and current slopes becomes difficult to maintain
Solution Approach 1:
The patent divides the semiconductor body into multiple cells, each with independent control electrodes and mesas. This segmentation allows different regions to perform different functions: some cells optimized for fast switching while others provide dV/dt control, resolving the contradiction between fast switching and slope control
Solution Approach 2:
The patent introduces auxiliary mesas with specific conductivity types as intermediary structures between the control electrodes and the main current path. These auxiliary mesas act as mediators that enable precise control over voltage and current slopes during switching transitions, allowing fast switching while maintaining slope controllability
2Measurement precision
If maximum voltage slope (dV/dt) control is implemented, then voltage slope control is improved, but switching duration increases leading to higher switching losses
Solution Approach 1:
The patent applies local quality by creating regions with different conductivity types and properties within the semiconductor body. Auxiliary mesas with specific doping concentrations are placed in specific locations to provide localized dV/dt control without affecting the overall fast switching performance of the device
Solution Approach 2:
The patent uses partial action by implementing dV/dt control only in specific regions through auxiliary mesas, rather than controlling the entire device uniformly. This allows voltage slope control to be applied partially where needed, maintaining fast switching in other regions and avoiding excessive switching duration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the controllability of the power semiconductor device, reducing switching losses and improving the slope control of voltage and current, thereby optimizing performance in high-voltage and high-current applications.
Implementation Method 1
an auxiliary mesa laterally confined by the source trench and one of the at least one control trench, the auxiliary mesa comprising a first semiconductor portion and a second semiconductor portion, both of the second conductivity type, wherein the auxiliary mesa is electrically connected to the first load terminal by means of the first semiconductor portion, and wherein the second semiconductor portion is arranged below the first semiconductor portion while being spatially displaced therefrom along the vertical direction
Data Source
AI summary
A power semiconductor device having an IGBT-configuration includes at least one power cell. Each power cell includes at least three trenches arranged laterally adjacent to each other. Each trench extends into a semiconductor body along a vertical direction and includes an insulator that insulates a respective electrode from the semiconductor body. The at least three trenches include at least one control trench whose electrode is electrically coupled to a control terminal, and a source trench whose electrode is electrically coupled to a first load terminal. An active mesa for conduction of at least a part of the load current is laterally confined at least by one of the at least one control trench and includes at least a respective section of each of a source region and a channel region. An auxiliary mesa is laterally confined by the source trench and one of the at least one control trench.