Semiconductor Diode Termination Region Electric Field Relaxation
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Solution Overview
Problem
Semiconductor devices, such as JBS diodes, face challenges in enhancing surge voltage withstand capability and preventing device destruction due to concentrated electric fields and breakdowns, particularly in the termination region.
Innovation Solution
The semiconductor device incorporates a specific structure with an n−-type semiconductor region, p-type semiconductor regions, and a P-N diode configuration, including a p+-type semiconductor region with higher impurity concentration, which forms an ohmic junction and relaxes the electric field, thereby reducing leakage and suppressing breakdowns in the termination region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Schottky barrier junction is used to achieve low on-voltage and low on-resistance characteristics, then rectification functionality is improved, but the device becomes vulnerable to surge voltage and electric field concentration causing breakdown
Solution Approach 1:
The patent applies local quality by creating a termination region with different impurity concentration (higher p-type doping) at the periphery compared to the center region. This local modification changes the electric field distribution specifically at the vulnerable termination region, reducing field concentration and preventing breakdown without affecting the low on-voltage characteristics of the main rectification region
Solution Approach 2:
The patent changes the impurity concentration parameter in the termination region, creating a graded or higher-doped p-type region at the periphery. This parameter change modifies the electric field distribution and breakdown characteristics, allowing the device to withstand surge voltage while maintaining normal rectification functionality in the center region
2Reliability
If the termination region is modified to distribute breakdown voltage, then surge voltage withstand capability is improved, but device complexity increases due to additional semiconductor regions
Solution Approach 1:
The patent segments the semiconductor device into distinct functional regions: a center region for normal rectification and a termination region at the periphery for surge voltage handling. This segmentation allows each region to be optimized for its specific function, with the termination region containing higher impurity concentration to distribute and handle breakdown voltage separately from the main rectification region
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 improves the semiconductor device's ability to withstand surge voltage by distributing the breakdown voltage and preventing device destruction, ensuring compatibility with low on-voltage and low on-resistance characteristics.
Implementation Method 1
The third semiconductor region forms an ohmic junction with the first electrode
Implementation Method 2
a Schottky barrier metal in contact with the n-type semiconductor region and the p-type semiconductor region
Implementation Method 3
The JBS diode has a structure for reducing leakage by relaxing the electric field at the interface between the n-type semiconductor region and the Schottky electrode under reverse bias
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first semiconductor region, a first electrode, a second semiconductor region, a third semiconductor region, a fourth semiconductor region, a fifth semiconductor region, and a second electrode. The first electrode forms a Schottky junction with the first region. The second region is provided between the first region and the first electrode. The third region is provided between the first region and the first electrode and forms an ohmic junction with the first electrode. The fourth region is provided between the first region and the third region. The fourth region has a higher impurity concentration than the first region. The fifth region is provided between the third region and the first electrode. The fifth region has a higher impurity concentration than the third region. The second electrode is provided on opposite side of the first region from the first electrode.