SiC Super Junction Pillars for Fast Switching and High Breakdown
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Solution Overview
Problem
Semiconductor devices using silicon carbide face challenges in achieving high switching speeds while maintaining a balance between breakdown voltage and ON resistance, as existing technologies struggle to optimize impurity concentration profiles for enhanced performance.
Innovation Solution
The semiconductor device employs a super junction structure with alternating n-type and p-type pillars having distinct impurity concentration layers, along with a manufacturing method that involves precise ion implantation and epitaxial growth to form layers with varying impurity concentrations, allowing for improved depletion layer integration and reduced ON resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silicon carbide is used as the semiconductor material, then the breakdown voltage is improved, but the switching speed is insufficient
Solution Approach 1:
The patent applies local quality by creating different impurity concentration profiles in different regions of the semiconductor device. Specifically, the first and second semiconductor layers have different average impurity concentrations (first average concentration and second average concentration), allowing localized optimization of electrical properties to achieve both high breakdown voltage and fast switching speed
Solution Approach 2:
The patent changes the impurity concentration parameter across different layers and regions. By controlling the impurity concentration to have a first average concentration in the first semiconductor layer and a second average concentration in the second semiconductor layer, the device achieves optimized performance characteristics that resolve the contradiction between breakdown voltage and switching speed
2Speed
If the impurity concentration is increased to reduce ON resistance, then the switching speed is improved, but the breakdown voltage decreases
Solution Approach 1:
The patent implements local quality by spatially distributing different impurity concentrations in different semiconductor layers. The first semiconductor layer has a first average impurity concentration while the second semiconductor layer has a second average impurity concentration, allowing each region to be optimized for its specific function without compromising the other
Solution Approach 2:
The patent resolves the contradiction by adding a vertical dimension to the impurity concentration distribution. Instead of uniform concentration throughout, the invention creates a multi-layer structure with different concentration profiles, transforming a one-dimensional problem into a three-dimensional solution space
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 enables higher breakdown voltage, suppressed ringing of output current, and increased switching speed, while maintaining a strong electric field resistance and reducing manufacturing complexity and costs.
Implementation Method 1
forming an epitaxial layer of the first conductivity type on the first semiconductor layer; forming a second semiconductor layer of the second conductivity type on the epitaxial layer
Implementation Method 2
injecting impurities of a second conductivity type into a first part of a first semiconductor layer; injecting impurities of the first conductivity type into a second part of the first semiconductor layer
Data Source
AI summary
A semiconductor device includes a first electrode, a first semiconductor layer of a first conductivity type on the first electrode, a first pillar of a second conductivity type on the first semiconductor layer, the first pillar having a first average concentration of impurities, a second pillar of the first conductivity type on the first semiconductor layer, and including a first layer having a second average concentration of impurities lower than the first average concentration, and a second layer having a third average concentration of impurities higher than the first average concentration, a second semiconductor layer of the second conductivity type on the second pillar, a third semiconductor layer of the first conductivity type on the second semiconductor layer, a second electrode connected to the first pillar and the third semiconductor layer, a third electrode, and an insulating film disposed between the second semiconductor layer and the third electrode.