Superjunction Charge-Balance Structure for Fast Switching
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Solution Overview
Problem
Super-junction semiconductor power devices with floating regions have low recombination-generation rates, leading to undesirable switching speeds, especially in wide band gap materials, and introducing point defects to increase switching speed also increases leakage current.
Innovation Solution
The design includes multi-layered drift regions with charge balance layers and connection regions that provide a direct path for carrier flow, independent of recombination-generation rates, reducing switching losses and increasing switching speed without significantly increasing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If point defects are introduced into the semiconductor material to increase recombination-generation rates, then switching speed is improved, but leakage current increases
Solution Approach 1:
The patent introduces connection regions as intermediary structures that provide a direct carrier transport path between the top region and charge balance regions, mediating the carrier flow to achieve fast switching without relying on point defects that would increase leakage current
Solution Approach 2:
The patent changes the structural parameters by introducing connection regions with specific conductivity types and configurations, transforming the carrier transport mechanism from recombination-generation dependent to direct path dependent, thereby improving switching speed without increasing leakage
2Loss of energy
If floating regions are used in super-junction devices, then conduction losses are reduced, but switching speed becomes dependent on low recombination-generation rates
Solution Approach 1:
The patent segments the drift region into multiple charge balance layers with embedded connection regions, creating a structured pathway that maintains the low conduction losses of floating regions while enabling fast switching through direct carrier transport
Solution Approach 2:
Connection regions serve as intermediaries that decouple the switching speed from recombination-generation rates by providing an alternative direct transport path for carriers, allowing the floating regions to maintain low conduction losses while switching speed is improved
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 faster switching speeds and reduced switching losses in super-junction devices while maintaining low conduction losses and high blocking voltages, using existing fabrication techniques for wide band gap semiconductor materials.
Implementation Method 1
connection regions that provide a direct path for carrier flow, independent of recombination-generation rates
Data Source
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AI summary
A super junction (SJ) device includes one or more charge balance (CB) layers. Each CB layer includes an epitaxial (epi) layer having a first conductivity type and a plurality of charge balance (CB) regions having a second conductivity type. Additionally, the SJ device includes a connection region having the second conductivity type that extends from a region disposed in a top surface of a device layer of the SJ device to one or more of the CB regions. The connection region enables carriers to flow directly from the region to the one or more CB regions, which decreases switching losses of the SJ device.