Super-Junction Pillar Extension for Edge Breakdown Control
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Solution Overview
Problem
Existing wide band gap super-junction power devices face premature breakdown due to electric field crowding near the edges of the active area during reverse bias operation, necessitating improved termination designs to manage the electric field effectively.
Innovation Solution
The implementation of multi-layered termination areas with specific doping arrangements, including junction termination extensions (JTE) and super-junction pillars, to gradually reduce the electric field magnitude and prevent premature breakdown, utilizing n-type and p-type doping regions arranged in various shapes such as annular or parallel rows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional junction termination is used, then the device structure is simple, but electric field crowding occurs near the edges of the active area causing premature breakdown
Solution Approach 1:
The termination structure is segmented into multiple functional regions: a first termination region with a first doping concentration and a second termination region with a second doping concentration. This segmentation allows each region to independently manage electric field distribution, preventing crowding at the active area edges while maintaining structural organization and improving breakdown voltage reliability.
Solution Approach 2:
Different doping concentrations are applied to different spatial regions of the termination area. The first termination region has a first doping concentration optimized for one aspect of field control, while the second termination region has a second doping concentration optimized for another aspect. This local differentiation of properties enables precise electric field management without requiring overly complex overall structures.
2Reliability
If the termination area is enlarged to reduce electric field crowding, then breakdown voltage improves, but the device area and manufacturing complexity increase
Solution Approach 1:
The invention changes the doping concentration parameter across different termination regions. By varying the doping concentration from the first value in the first termination region to the second value in the second termination region, the electric field distribution is optimized to achieve high blocking voltage without requiring excessive termination area extension.
Solution Approach 2:
Instead of simply extending the termination area in one dimension, the invention introduces a new dimension of control through multi-region segmentation with different doping concentrations. This allows electric field management in a more sophisticated manner, achieving high blocking voltage with optimized area utilization.
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 proposed design enhances the blocking voltage and ensures reliable operation under high-temperature and high-voltage conditions by effectively managing electric field crowding, thereby preventing premature device breakdown.
Implementation Method 1
a junction termination allows a gradual reduction of the magnitude of the electric field over a termination area of the device surrounding the active area of the device
Implementation Method 2
implanting an active area of the first epi layer and a termination area of the first epi layer with a first set of SJ pillars that comprise a particular doping concentration of a first conductivity type
Data Source
AI summary
A super-junction (SJ) device includes a first epitaxial (epi layer) that forms a first SJ layer of the SJ device and includes a second epi layer disposed on the first SJ layer that forms a device layer of the SJ device. An active area and a termination area of the first epi layer includes a first set of SJ pillars that have a particular doping concentration of a first conductivity type and a second set of SJ pillars that have the particular doping concentration of a second conductivity type. A termination area of the second epi layer includes one or more implanted regions that form a junction termination that overlaps with at least one SJ pillar of the first set of SJ pillars or the second set of SJ pillars in the termination area of the first epi layer.