Guard Ring Structure for Electric Field Suppression
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Solution Overview
Problem
Existing semiconductor devices with guard rings face challenges in uniformly reducing the electric field in the outer circumferential voltage withstanding region, leading to higher field concentrations near inner guard rings and potential avalanche breakdown.
Innovation Solution
The semiconductor device design features inner and outer circumferential guard rings with varying widths and intervals, where inner guard rings have a greater width and narrower intervals than outer guard rings, and includes high and low concentration regions within the guard rings to enhance depletion layer extension and reduce electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the width of inner circumferential guard rings is increased to suppress electric field, then electric field suppression improves, but device complexity increases
Solution Approach 1:
The patent resolves the complexity issue by applying local quality - only specific guard rings (inner circumferential) require increased width for electric field suppression, while outer circumferential guard rings can maintain standard dimensions. This localized approach achieves the necessary electric field control without uniformly increasing the complexity of the entire guard ring system.
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 effectively suppresses high electric fields around both inner and outer guard rings, ensuring high withstanding voltage and preventing avalanche breakdown, while maintaining sufficient depletion layer extension in the outer drift region.
Implementation Method 1
When the depletion layer reaches the guard ring on innermost side, the depletion layer further extends from that guard ring toward the outer circumferential side. When the depletion layer reaches the second guard ring from the inner circumferential side, the depletion layer further extends from that second guard ring toward the outer circumferential side.
Implementation Method 2
inner guard rings have a greater width and narrower intervals than outer guard rings. By making the interval between the guard rings on the inner circumferential side narrower, electric field in the vicinity of the guard rings on the inner circumferential side can be suppressed.
Implementation Method 3
Upon when the diode turns on, current flows from the front surface electrode toward the rear surface electrode.
Data Source
AI summary
A semiconductor device may include an element region and a peripheral voltage withstanding region. The peripheral voltage withstanding region includes inner circumferential guard rings; and outer circumferential guard rings having a width narrower than a width of the inner circumferential guard rings. An interval between the inner circumferential guard rings is narrower than an interval between the outer circumferential guard rings. Each of the inner circumferential guard rings includes a first high concentration region and a first low concentration region. Each of the outer circumferential guard rings includes a second high concentration region and a second low concentration region. A width of a part of each first low concentration region that is exposed on a front surface of the semiconductor device is wider than a width of a part of each second low concentration region that is exposed on the front surface.