High-Voltage Edge Termination Structure for Surface Charge Tolerance
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Solution Overview
Problem
High voltage edge termination structures in power semiconductor devices are sensitive to surface charge variations, leading to potential breakdown at lower applied voltages, and existing solutions like multi-zone junction termination extension (MZ-JTE) require larger areas for implementation.
Innovation Solution
A high voltage edge termination structure comprising a semiconductor body with a JTE region, a heavily doped channel stop region, and a plurality of field plates or depletable guard rings, which are formed using ion implantation to minimize depletion region shrinkage and increase tolerance to surface charge variations without significantly increasing the implementation area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If JTE structure is used to minimize area, then area is reduced, but surface charge tolerance deteriorates
Solution Approach 1:
The termination region is divided into multiple zones with different doping concentrations (first, second, and third doping concentrations), creating distinct functional regions that collectively improve surface charge tolerance while maintaining compact area. The segmented doping profile allows each zone to contribute differently to field control and charge compensation.
Solution Approach 2:
Different regions of the termination structure are assigned different doping concentrations to perform specialized functions: the first doping concentration region controls peak field, the second doping concentration region provides charge compensation, and the third doping concentration region ensures proper field distribution. This local differentiation enables improved surface charge tolerance within limited area.
2Reliability
If MZ-JTE structure is used to improve surface charge tolerance, then reliability is improved, but area increases
Solution Approach 1:
The patent combines multiple doping concentration regions within a unified termination structure, merging the functions of field control and charge compensation into a single integrated design. This consolidation achieves improved surface charge tolerance without requiring the additional area that separate structures would demand.
Solution Approach 2:
Instead of expanding area to improve surface charge tolerance, the patent utilizes the vertical dimension by creating a multi-layered doping profile with different concentrations at different depths and lateral positions. This three-dimensional doping architecture achieves enhanced reliability within the same planar footprint.
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 structure effectively prevents breakdown at lower voltages by modulating the doping concentration and electric field distribution, achieving breakdown voltages over 1200V for both low and high surface charge cases with minimal area increase.
Implementation Method 1
formed using ion implantation to minimize depletion region shrinkage and increase tolerance to surface charge variations
Implementation Method 2
modulating the doping concentration and electric field distribution, achieving breakdown voltages over 1200V
Data Source
AI summary
A high voltage edge termination structure for a power semiconductor device is provided. The high voltage edge termination structure comprises a semiconductor body of a first conductive type, a JTE region of a second conductive type, a heavily doped channel stop region of the first conductive type, and a plurality of field plates. The JTE region is formed in the semiconductor body, wherein the JTE region is adjacent to an active region of the power semiconductor device. The heavily doped channel stop region is formed in the semiconductor body, wherein the heavily doped channel stop region is spaced apart from the JTE region. The plurality of field plates is formed on the JTE region.