Trench-Based Edge Termination for Semiconductor Components
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Solution Overview
Problem
High voltage power switching devices face a trade-off between breakdown voltage and on-state resistance, with existing edge termination structures either occupying large area or being costly to manufacture, while also requiring enhanced avalanche current handling at the interface between the active and termination regions.
Innovation Solution
A semiconductor component with a trench-based edge termination structure that includes a floating gate electrode and a non-floating termination electrode, allowing for reduced electric field across the gate oxide and optimized spacing between trenches for reduced on-resistance, while being cost-efficient to manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If charge balancing structures are formed in the drift region to maintain uniform electric field, then breakdown voltage increases, but edge termination structures occupy large area
Solution Approach 1:
The patent transitions from planar charge balancing structures to a three-dimensional trench-based termination structure. The trench extends vertically into the drift region, creating a vertical dimension for electric field management. This allows charge balancing to occur within the trench volume rather than requiring extensive lateral area, thus achieving high breakdown voltage with compact footprint.
Solution Approach 2:
The trench structure nests multiple functional elements within a compact vertical space. The charge balancing structures are positioned within the trench, which itself is embedded in the drift region. This nested arrangement consolidates what would otherwise require large lateral separation into a compact vertical configuration, reducing the area occupied by edge termination structures.
2Reliability
If field limiting rings and channel stop regions are used to reduce leakage and enhance breakdown, then device reliability improves, but manufacturing cost increases
Solution Approach 1:
The trench structure serves multiple functions simultaneously: it acts as a field limiting structure, provides charge balancing, functions as a channel stop, and serves as an isolation region. By consolidating these previously separate structures into a single integrated trench feature, the patent reduces the number of manufacturing steps and material layers required, thereby lowering manufacturing cost while maintaining or improving device reliability.
3Strength
If thicker field oxide is used to reduce electric field curvature, then breakdown voltage increases, but on-state resistance increases
Solution Approach 1:
The patent applies different oxide thicknesses to different regions: thicker oxide is placed specifically at the trench interface where electric field curvature is highest and breakdown is most critical, while thinner oxide or no oxide is used in regions where low on-state resistance is prioritized. This localized differentiation allows the device to achieve high breakdown voltage at the termination region without sacrificing on-state conductivity in the active channel 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
The semiconductor component achieves higher breakdown voltage, improved reliability, and reduced on-resistance by utilizing a trench-based edge termination structure with a floating gate electrode, enhancing the balance between breakdown voltage and on-state resistance while maintaining cost-effectiveness.
Implementation Method 1
allowing for reduced electric field across the gate oxide
Implementation Method 2
enhancing the balance between breakdown voltage and on-state resistance while maintaining cost-effectiveness
Data Source
AI summary
A semiconductor component that includes an edge termination structure and a method of manufacturing the semiconductor component. A semiconductor material has a semiconductor device region and an edge termination region. One or more device trenches may be formed in the semiconductor device region and one or more termination trenches is formed in the edge termination region. A source electrode is formed in a portion of a termination trench adjacent its floor and a floating electrode termination structure is formed in the portion of the termination trench adjacent its mouth. A second termination trench may be formed in the edge termination region and a non-floating electrode may be formed in the second termination trench. Alternatively, the second termination trench may be omitted and a trench-less non-floating electrode may be formed in the edge termination region.