IGBT Body Region Sub-Structure for Hole Current Redistribution
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Solution Overview
Problem
Existing IGBTs face a trade-off between low collector-emitter saturation voltage (VCEsat) and switching losses, as high hole plasma concentration for low VCEsat increases switching losses, making it difficult to achieve optimal performance in power semiconductor devices.
Innovation Solution
The implementation of a p-doped body region with a sub region of reduced hole mobility, embedded within the semiconductor substrate, which redistributes hole current and concentrates holes in regions of high electron current, thereby reducing VCEsat and switching losses while maintaining turn-off performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If high hole plasma concentration is used to achieve low VCEsat, then the collector-emitter saturation voltage is reduced, but switching losses increase
Solution Approach 1:
The patent applies local quality by creating a sub region with different doping concentration (lower hole mobility) within the body region. This localized modification allows holes to be concentrated in specific areas (high electron current regions) while maintaining low hole plasma concentration in the drift region, thereby achieving low VCEsat without increasing switching losses.
Solution Approach 2:
The body region is segmented into a main body region and a sub region with different electrical properties. The sub region has lower hole mobility due to different doping concentration, creating distinct functional zones that separately optimize for low VCEsat and reduced switching losses.
2Reliability
If high hole plasma concentration is used to achieve low VCEsat, then the conducting on-state resistance is reduced, but turn-off performance deteriorates
Solution Approach 1:
By creating a sub region with lower hole mobility through different doping concentration, the patent achieves local optimization where hole concentration is enhanced in specific areas for low VCEsat while the overall hole plasma concentration in the drift region remains controlled for good turn-off performance.
3Loss of energy
If the semiconductor device structure is modified to reduce switching losses, then energy efficiency improves, but device complexity increases
Solution Approach 1:
The patent modifies only a specific sub region within the body region by changing the doping concentration to create lower hole mobility. This localized modification achieves reduced switching losses without significantly increasing overall device complexity, as the basic device structure remains intact.
Solution Approach 2:
The patent changes the doping concentration parameter in the sub region to create different hole mobility characteristics. This parameter modification allows optimization of switching losses while maintaining a relatively simple device structure that is compatible with existing manufacturing processes.
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 improves the trade-off between turn-off performance and VCEsat by reducing hole plasma concentration in the drift region, resulting in lower switching losses and maintaining a low VCEsat, enhancing the overall efficiency of power semiconductor devices.
Implementation Method 1
an embedded structure having a hole mobility which is lower than hole mobility of adjoining semiconductor regions
Data Source
AI summary
A bipolar semiconductor device with a hole current redistributing structure and an n-channel IGBT are provided. The n-channel IGBT has a p-doped body region with a first hole mobility and a sub region which is completely embedded within the body region and has a second hole mobility which is lower than the first hole mobility. Further, a method for forming a bipolar semiconductor device is provided.