Segmented Trench Gate IGBT Reduces On-Resistance and Turn-off Loss
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Solution Overview
Problem
IGBTs with trench gate structures face a trade-off between reducing on-resistance and turn-off loss, as increasing carrier concentration to lower on-resistance prolongs turn-off time and increases loss during turn-off.
Innovation Solution
A semiconductor device with a trench gate structure that includes multiple independently biased gate electrodes and a specific doping profile to control carrier density, allowing for reduced on-resistance while minimizing turn-off loss by managing carrier discharge through independent gate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If carrier concentration is increased to reduce on-resistance, then on-resistance is reduced, but turn-off time becomes prolonged and turn-off loss increases
Solution Approach 1:
The gate structure is segmented into multiple independent gate electrodes (first gate electrode, second gate electrode, third gate electrode) that can be controlled separately. This segmentation allows different regions of the semiconductor device to be operated at different times, enabling the emitter region to be turned off before the collector region, thereby reducing turn-off time and turn-off loss while maintaining low on-resistance through the accumulated carriers during the on-state.
2Loss of energy
If trench gate structure is used to increase channel density, then on-resistance is reduced, but carrier discharge time increases
Solution Approach 1:
The gate structure is segmented into multiple independent gate electrodes (first gate electrode, second gate electrode, third gate electrode) that can be controlled separately. This segmentation allows different regions of the semiconductor device to be operated at different times, enabling the emitter region to be turned off before the collector region, thereby reducing turn-off time and turn-off loss while maintaining low on-resistance through the accumulated carriers during the on-state.
Solution Approach 2:
The first gate electrode is turned off before the second and third gate electrodes. This preliminary action removes carriers from the emitter region in advance, creating a low-carrier state in the emitter before the collector region is turned off. This preliminary carrier removal reduces the total number of carriers that need to be discharged during the complete turn-off process, thereby reducing turn-off loss.
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 semiconductor device achieves reduced on-resistance and switching loss by controlling carrier density and accelerating the turn-off process, thereby improving conversion efficiency.
Implementation Method 1
electrically insulated from the semiconductor substrate via a first insulating film and electrically insulated from the first electrode via a second insulating film
Implementation Method 2
biased independently from the first control electrode
Implementation Method 3
a fourth semiconductor layer of the first conductivity type between the first semiconductor layer and the second electrode and between the first semiconductor layer and the third control electrode and having a higher concentration of a first conductivity type impurity than the first semiconductor layer
Data Source
AI summary
A semiconductor device includes a semiconductor substrate including first and second surfaces, and a first semiconductor layer of a first conductivity type, a first electrode on the first surface, a first control electrode that is inwardly from the first surface and electrically insulated from the semiconductor substrate and the first electrode, a second control electrode that is inwardly from the first surface, electrically insulated from the semiconductor substrate and the first electrode via a fourth insulating film, and biased independently from the first control electrode, a third control electrode on the second surface and electrically insulated from the semiconductor substrate, and a second electrode on the second surface and electrically connected to the semiconductor substrate.