SiC MOSFET Termination Region Defect Detection via Schottky Diode
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Solution Overview
Problem
Wide-bandgap semiconductor devices, such as SiC-MOSFETs, face challenges in securing reliability and stability due to crystal defects in the termination region, which are not effectively evaluated by existing screening methods, leading to potential power loss and malfunction when used as freewheel diodes.
Innovation Solution
Incorporating a defect detection device, such as a Schottky barrier diode, in the termination region of the semiconductor device to detect and evaluate crystal defects through forward and reverse characteristic analysis, ensuring the reliability of the body diode and stability of device operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current stress is applied to the body diode in the active region, then crystal defects in the active region are expanded to saturation, but crystal defects in the termination region cannot be fully expanded
Solution Approach 1:
The patent divides the semiconductor device into two functional regions: the active region containing the body diode for normal operation, and the termination region containing a dedicated defect detection device. This segmentation allows different screening functions to be performed in different regions, enabling comprehensive defect detection that covers both the active region and termination region, thereby resolving the limitation of previous single-region screening methods
Solution Approach 2:
The defect detection device in the termination region acts as an intermediary indicator structure that reflects the quality of the entire semiconductor layer including the active region. By detecting defects in the termination region, the patent indirectly identifies potential defects that could affect the body diode in the active region, providing a comprehensive screening mechanism without requiring direct stress testing of the active region
2Measurement precision
If a defect detection device is added in the termination region, then defect detection capability is improved, but device complexity increases
Solution Approach 1:
The defect detection device in the termination region uses the same basic diode structure as the body diode in the active region, sharing common manufacturing processes and material layers. This universal design allows the detection function to be integrated without requiring entirely new device structures, thereby improving defect detection capability while minimizing the increase in device complexity
Solution Approach 2:
The defect detection device utilizes the inherent bipolar operation characteristics of the semiconductor material itself to detect defects. By applying current stress and measuring forward resistance changes, the detection device uses the material's own physical properties (carrier recombination energy, crystal defect expansion) as the detection mechanism, eliminating the need for external complex testing equipment and simplifying the overall system
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
The defect detection device effectively identifies and evaluates crystal defects in the termination region, enhancing the reliability of the body diode and ensuring stable device operation by preventing the expansion of defects during freewheel current flow, thereby improving the overall performance and reliability of the semiconductor device.
Implementation Method 1
An SiC semiconductor device has a problem in that a bipolar operation using p-type and n-type carriers leads to expansion of a crystal defect due to carrier recombination energy
Data Source
AI summary
Provided is a semiconductor device including an active region provided in a first conductivity type semiconductor layer and a termination region provided around the active region. A MOS transistor through which a main current flows in a thickness direction of the semiconductor layer is formed in the active region. The termination region includes a defect detection device provided along the active region. The defect detection device includes a diode including a first main electrode provided along the active region on a first main surface of the semiconductor layer, and a second main electrode provided on a second main surface side of the semiconductor layer.