Contact us

Une nouvelle fenêtre s'ouvre Une nouvelle fenêtre s'ouvre

Principle of Operation

Cross-sectional structure of an IGBT and the factors that limit its collector-emitter voltage

Figure A shows the cross-sectional structure of a conventional IGBT and the carrier distribution in the N-base region. The carrier concentration decreases monotonically across the N-base region from the collector electrode to the emitter electrode. In order to increase the collector-emitter voltage of an IGBT, a deep N-base region is necessary between the collector and emitter electrodes. However, a deep N-base region leads to an area with lower carrier concentration. The consequent increase in electrical resistance results in an increase in voltage drop and thus an increase in on-state voltage.

Characteristics of the IEGT gate structure and the injection enhancement (IE) effect

Figure B shows the cross-sectional structure of and the carrier distribution in an IEGT. The IEGT has an IGBT-like structure with deeper and wider trench gates than the IGBT. This structure increases the gate-to-emitter resistance, preventing carriers from passing through the emitter side. Consequently, carrier concentration is enhanced near the emitter electrode in the N-base region. As this phenomenon has the same effect as carrier injection and accumulation, it is called the injection enhancement (IE) effect. This trench-gate structure helps reduce an increase in voltage drop even at high collector-emitter voltage rating.

Cross-Sectional View of and Carrier Distribution in an IGBT

Figure A Cross-Sectional View of and Carrier Distribution in an IGBT

Because carrier concentration near the emitter is low, an increase in the collector-emitter voltage rating leads to an increase in on-state voltage.

Cross-Sectional View of and Carrier Distribution in an IEGT

Figure B Cross-Sectional View of and Carrier Distribution in an IEGT

Carrier concentration near the emitter is enhanced near the emitter. Consequently, electron injection increases, reducing on-state voltage.

Contacts

Pour toute question, cliquez sur l'un de ces liens :

Questions techniques
Questions concernant les achats, l'échantillonnage et la fiabilité des circuits intégrés
To Top
·Before creating and producing designs and using, customers must also refer to and comply with the latest versions of all relevant TOSHIBA information and the instructions for the application that Product will be used with or for.