Semiconductor Device Field Limiting Regions Coupling Plate Electrodes
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Solution Overview
Problem
MOS transistors with a super junction structure face challenges in achieving high breakdown voltage while maintaining low on-resistance, as the electric field concentration at the periphery can lead to sharp depletion layer rise and reduced breakdown voltage.
Innovation Solution
The semiconductor device incorporates second conductivity-type columnar regions arranged in a ring shape, field limiting regions connected to these columns, and coupling plate electrodes that are capacitively coupled to limit electric field concentration, preventing sharp depletion layer rise and increasing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If p-type and n-type columnar regions are regularly arranged in a repeated pattern to achieve complete depletion of the drift region, then low on-resistance is achieved, but electric field concentration at the periphery causes sharp depletion layer rise and reduced breakdown voltage
Solution Approach 1:
The patent applies local quality by making the columnar regions in the peripheral region different from those in the element region. Specifically, the peripheral region has columnar regions with different doping concentrations or dimensions to create a gradual transition of the depletion layer, thereby reducing electric field concentration at the periphery while maintaining the low on-resistance characteristic in the element region.
Solution Approach 2:
The patent segments the semiconductor device into distinct element region and peripheral region with different columnar region configurations. This segmentation allows independent optimization of each region: the element region maintains the regular repeated pattern for low on-resistance, while the peripheral region uses modified columnar regions to control electric field distribution and improve breakdown voltage.
2Reliability
If high-temperature processing is used to adjust impurity distribution, then breakdown voltage can be improved, but columnar regions broaden which increases on-resistance
Solution Approach 1:
The patent changes the doping concentration parameters of the columnar regions in the peripheral region to create a gradient profile. By adjusting the impurity concentration rather than using high-temperature processing, the depletion layer can be extended to improve breakdown voltage without causing lateral diffusion that would broaden the columnar regions and increase on-resistance.
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 increases the breakdown voltage by stabilizing the potential distribution and preventing electric field concentration, while maintaining low on-resistance without requiring high-temperature processing that could broaden columnar regions.
Implementation Method 1
coupling plate electrodes that are capacitively coupled to limit electric field concentration
Implementation Method 2
preventing sharp depletion layer rise and increasing breakdown voltage
Data Source
AI summary
A field limiting regions are arranged in the upper surface of a semiconductor region in the peripheral region and connected to upper portions of at least some of columnar regions. An insulating film is provided on the semiconductor region in the peripheral region and covering a field limiting region. A coupling plate electrode is provided above a pair of the field limiting regions adjacent to each other in a direction from a boundary between the element region and the peripheral region to an outer edge of the peripheral region. The joint field regions are in contact with one of the pair of field limiting regions on a boundary side in an opening formed in the insulating film, and reaching the other one of the pair of the field limiting regions on an outer edge side with the insulating film interposed therebetween.