Semiconductor Edge Termination Using NP-Buffer Pillar Structures
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Solution Overview
Problem
Current edge termination structures in semiconductor devices face challenges in balancing high breakdown voltage (BV) and low on-state resistance (RS), often requiring large termination areas that increase device size and lead to high edge electric fields, which can damage connected devices.
Innovation Solution
The implementation of an NP-buffer-PN or NP-buffer-N pillar edge termination structure, which reduces the termination area while minimizing edge electric fields by sustaining lateral electric potential drops and blocking voltage, thereby reducing the extension of electric potential lines to the edge of the semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional edge termination structures (floating rings and field plates) are used, then breakdown voltage is improved, but on-state resistance increases and device size increases
Solution Approach 1:
The termination structure is segmented into multiple alternating P-type and N-type doped regions arranged in a sequence, creating a multi-layered charge balance structure that distributes the voltage blocking function across multiple segments rather than relying on a single termination layer
Solution Approach 2:
The patent applies different doping types (P-type and N-type) and different doping concentrations to adjacent regions within the termination structure, creating local variations in electrical properties that enable both high breakdown voltage and low on-state resistance in different parts of the structure
2Area of stationary object
If termination area is reduced, then device size is reduced, but edge electric fields increase causing device damage
Solution Approach 1:
The patent transitions from two-dimensional planar termination structures to a three-dimensional vertical stack of alternating P-type and N-type doped regions, utilizing the vertical dimension to extend the voltage blocking capability without increasing the horizontal termination area
Solution Approach 2:
The termination structure uses a composite arrangement of P-type and N-type doped regions with different electrical properties, creating a charge balance structure where opposite polarity regions work together to distribute and reduce edge electric fields while maintaining compact dimensions
3Reliability
If superjunction GCB termination is used, then on-state resistance is reduced, but termination area must be large (>200 μm)
Solution Approach 1:
The patent employs a vertical stacking architecture where alternating P-type and N-type doped regions are arranged in the depth direction, enabling the termination structure to achieve both low on-state resistance and high breakdown voltage within a compact lateral footprint by utilizing the vertical dimension for charge balance
Solution Approach 2:
The termination structure is divided into multiple alternating P-type and N-type doped regions stacked vertically, with each segment contributing to the overall charge balance and voltage blocking capability, allowing the structure to achieve superior electrical performance in a reduced area compared to conventional GCB 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 approach allows for a reduced termination area with lower on-state resistance and high breakdown voltage, maintaining device safety from high electric fields and avoiding BV degradation, while being compatible with existing structures like field plates and floating rings.
Implementation Method 1
an NP-buffer-PN or NP-buffer-N pillar edge termination structure, which reduces the termination area while minimizing edge electric fields by sustaining lateral electric potential drops and blocking voltage
Data Source
AI summary
At least one embodiment is directed to a semiconductor edge termination structure, where the edge termination structure comprises several doped layers and a buffer layer.