Power Semiconductor Barrier Structure for Predictable dI/dt
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Solution Overview
Problem
Existing power semiconductor devices face challenges in accurately predicting and controlling the rate of change of load current (dI/dt) and collector/emitter voltage (dV/dt), as well as achieving low switching and conduction losses, due to discrepancies between simulated and actual values.
Innovation Solution
The device incorporates a deep semiconductor region with a high dopant concentration, a trench structure, and a barrier structure to control hole transfer, enhancing the prediction and control of dI/dt characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional power semiconductor device structure is used, then manufacturing is simpler, but dI/dt prediction accuracy is poor and switching losses are high
Solution Approach 1:
The device is segmented into distinct functional regions: an active region with control trenches for current modulation, and a hole accumulation region with high dopant concentration for charge storage. This segmentation allows independent optimization of dI/dt control and switching characteristics, improving prediction accuracy without excessive complexity
Solution Approach 2:
The patent introduces a vertical dimension by creating a deep hole accumulation region extending downward from the active region, and uses trench structures that penetrate through the device thickness. This three-dimensional architecture enables new mechanisms for controlling dI/dt that are not available in planar devices
2Loss of energy
If the active region is designed for low switching losses, then energy efficiency improves, but dI/dt control becomes difficult to predict
Solution Approach 1:
The hole accumulation region is pre-formed during manufacturing with a specific high dopant concentration (at least twice that of the drift region). This preliminary charge storage capability is built into the device structure before operation, enabling predictable dI/dt control during switching events without increasing switching losses
Solution Approach 2:
The patent changes the dopant concentration parameter by creating a deep region with at least twice the dopant concentration of the drift region. This parameter change fundamentally alters the charge distribution and enables independent control of switching losses and dI/dt characteristics
3Adaptability or versatility
If control trenches are added to control load current, then dI/dt control capability improves, but device complexity increases
Solution Approach 1:
The control trenches serve multiple functions: they provide the control electrode for modulating load current, they define the boundary between active and termination regions, and they facilitate the formation of the hole accumulation region. This multi-functionality reduces the need for additional separate structures
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 allows for improved control of dI/dt characteristics by preventing hole transfer from the active region to the edge termination region, thereby improving the accuracy of dI/dt prediction and reducing switching losses.
Implementation Method 1
a deep semiconductor region of a first conductivity type, which exhibits a dopant concentration of at least twice as high as the dopant concentration of the semiconductor drift region
Data Source
AI summary
In a power semiconductor device, a deep semiconductor region is provided in addition to a barrier structure. The barrier structure is spatially separated from a trench structure in an active region and arranged in a transition region between the active region and an edge termination region of the power semiconductor device.