IGBT Edge Terminal Structure for Stable Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor devices face fluctuations in breakdown voltage due to variations in doping concentrations and electric field concentrations, particularly in the edge terminal structure, which affect the reliability and performance of insulated gate bipolar transistors (IGBTs).
Innovation Solution
A semiconductor device with a bulk donor of a first conductivity type distributed throughout the substrate, featuring an edge terminal structure with high concentration regions and guard rings, where hydrogen implantation creates a hydrogen peak portion and a second high concentration region to control doping concentrations and mitigate electric field concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a P type guard ring is provided in an outer peripheral part of an N type semiconductor substrate, then breakdown voltage is improved, but fluctuation of breakdown voltage occurs due to variations in doping concentrations and electric field concentrations
Solution Approach 1:
The patent applies local quality by creating a first high concentration region with donor concentration higher than the bulk donor concentration in the edge terminal structure portion. This localized high doping concentration region specifically addresses the electric field concentration at the peripheral part of the semiconductor substrate, reducing breakdown voltage fluctuation while maintaining improved breakdown voltage characteristics.
Solution Approach 2:
The patent changes the doping concentration parameter by introducing a first high concentration region with donor concentration higher than the bulk donor concentration. This parameter change in the edge terminal structure portion modifies the electric field distribution, thereby stabilizing the breakdown voltage and reducing its fluctuation.
2Manufacturing precision
If hydrogen implantation is used to create high concentration regions, then doping concentration control is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by performing hydrogen implantation to create the first high concentration region in the edge terminal structure portion before final device fabrication steps. This preliminary doping concentration control establishes the necessary electric field distribution early in the manufacturing process, simplifying subsequent fabrication steps.
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 solution stabilizes the breakdown voltage by controlling doping concentrations and reducing electric field concentrations, enhancing the reliability and performance of semiconductor devices, particularly IGBTs, by forming specific high concentration regions and guard rings.
Implementation Method 1
hydrogen implantation creates a hydrogen peak portion and a second high concentration region to control doping concentrations and mitigate electric field concentrations
Data Source
AI summary
A semiconductor device includes trench portions arrayed in a first direction on an upper surface side of a semiconductor substrate, a first conductivity type lower surface region provided in a part of a lower surface of the semiconductor substrate, a second conductivity type base region provided on the upper surface side, a first conductivity type first region disposed between the base region and the lower surface region, a first conductivity type upper surface region provided on an upper surface of the semiconductor substrate, and a second conductivity type bottom region disposed continuously in the first direction to be in contact with bottom portions of the trench portions. In a cross section along the first direction and perpendicular to the upper and lower surfaces and passing through the lower surface region, one end portion of the bottom region in the first direction locates directly above the lower surface region.