Reverse-Conducting IGBT With Segmented Control Electrodes
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Solution Overview
Problem
In reverse-conducting IGBTs, improving diode characteristics without affecting IGBT characteristics is challenging, leading to suboptimal performance in both IGBT and diode modes.
Innovation Solution
The semiconductor device incorporates a specific layered structure with multiple conductivity type semiconductor layers and control electrodes, strategically positioned and insulated to enhance hole injection and electron injection, reducing conduction and switching losses by controlling impurity concentrations and applying independent control voltages to control electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a reverse-conducting IGBT structure is used to integrate IGBT and diode functions, then device versatility is improved, but the ability to independently optimize diode and IGBT characteristics deteriorates
Solution Approach 1:
The patent divides the semiconductor device into distinct functional regions: an IGBT region with gate electrodes for controlled switching and a diode region without gate electrodes for reverse conduction. This segmentation allows independent optimization of each component's characteristics while maintaining integration in a single chip structure.
Solution Approach 2:
Different regions of the semiconductor device are given different structural qualities: the IGBT region has a specific layered structure with emitter, base, and collector layers optimized for switching, while the diode region has a simplified structure optimized for reverse conduction. This local differentiation enables each region to perform its function optimally.
2Reliability
If conventional IGBT structure is used, then IGBT characteristics are maintained, but diode characteristics cannot be improved
Solution Approach 1:
The semiconductor device is segmented into an IGBT region that maintains conventional IGBT structure for reliable switching operation, and a diode region with modified structure for improved reverse conduction characteristics. The segmentation allows the diode region to be optimized independently without compromising IGBT performance.
Solution Approach 2:
The diode region is given local structural modifications including specific doping concentrations and layer configurations that differ from the IGBT region, enabling improved diode characteristics such as lower forward voltage and faster recovery while the IGBT region maintains its optimized structure.
3Measurement precision
If multiple control electrodes are added to independently control IGBT and diode regions, then control precision is improved, but device complexity increases
Solution Approach 1:
The control electrode structure is segmented into first control electrodes positioned over the IGBT region and second control electrodes positioned over the diode region. This segmentation enables independent voltage control of each region, providing precise control of switching and reverse conduction timing.
Solution Approach 2:
The control electrodes serve multiple functions: they control the IGBT switching operation, regulate the diode reverse conduction timing, and can be used to optimize both forward and reverse characteristics. This multi-functionality reduces the need for separate control mechanisms.
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 reduces conduction and switching losses in both IGBT and diode modes by optimizing impurity concentrations and control voltage application, improving overall device performance.
Implementation Method 1
a first control electrode provided between the semiconductor part and the first electrode, the first control electrode being positioned in a first trench provided at the first surface side of the semiconductor part, the first control electrode being electrically insulated from the semiconductor part by a first insulating film; a second control electrode provided between the semiconductor part and the first electrode, the second control electrode being positioned in a second trench provided at the first surface side of the semiconductor part, the second control electrode being electrically insulated from the semiconductor part by a second insulating film
Implementation Method 2
a third control electrode provided between the semiconductor part and the first electrode, the third control electrode being positioned in a third trench provided at the first surface side of the semiconductor part, the third control electrode being electrically insulated from the semiconductor part by a third insulating film and electrically isolated from the first and second control electrodes
Implementation Method 3
The third semiconductor layer is selectively provided between the first semiconductor layer and the first electrode, the third semiconductor layer including a second-conductivity-type impurity with a higher concentration than a concentration of a second-conductivity-type impurity in the second semiconductor layer
Data Source
AI summary
A semiconductor device includes a first electrode on a first surface of a semiconductor part, a second electrode on a second surface opposite to the first surface, and first and second control electrodes in trenches, respectively, at a first surface side. The semiconductor part includes first to sixth layers. The second and third layers of a second conductivity type are selectively provided between the first layer of a first conductivity type and the first electrode. The third layer includes a second conductivity type impurity with a higher concentration than a concentration of a second-conductivity-type impurity in the second layer. The fourth layer of the first conductivity type is selectively provided between the second layer and the first electrode. The fifth layer of the second conductivity type and the sixth layer of the first conductivity type are selectively provided between the first layer and the second electrode.