What are RC-IGBTs and IEGTs?

Reverse conductive IGBT : RC-IGBT

  • The structure of the RC-IGBT is shown in Fig. 3-16 (a). A diode is formed by making a part of the p-type layer, which is the collector of the IGBT, n-type. This diode has the same function as FWD * 1, which is generally inserted in the IGBT.
  • With the introduction of thin wafer technology, it became possible to commercialize this configuration. Since the diode and the IGBT are one chip, , it is easy to assemble. Because it is difficult to control the performance of the diode and the IGBT separately, the RC-IGBT is unsuitable for certain applications.

*1: FWD—Free-Wheeling Diode. Generally, it is used to send reflux current generated by a reactor.

Structure of RC-IGBT
Fig. 3-16(a) Structure of RC-IGBT

Injection-enhanced gate transistor : IEGT

  • Generally, in the high-voltage IGBT, it is difficult to obtain low VCE (sat) characteristics because the carrier concentration of the drift layer (n-type layer) on the emitter side is low.
  • The IEGT was developed to obtain low VCE (sat) performance at high withstand voltage (generally 1200 V or higher).
  • Fig. 3-16(b) shows the IEGT’s structure and principle.
  • It has a trench gate structure. Drawing out of the gate electrode is thinned out.  As a result, carriers are accumulated just under the thinned gate electrode, increasing the carrier concentration on the emitter side.
  • This high carrier density decreases resistance of drift layer, and makes VCE (sat) low.


Structure and carrier density of IEGT
Fig. 3-16(b) Structure and carrier density of IEGT

Chapter III : Transistors

Types of Transistors
Bipolar Transistors (BJTs)
Bias Resistor Built-in Transistors (BRTs)
Junction Field-Effect Transistors (JFETs)
Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs)
Differences between BJT and MOSFET
Structure and Operation of MOSFET
MOSFET Performance Improvement: Decision Factors of RDS(ON)
MOSFET Performance Improvement: Approach to Low RDS(ON)
MOSFET Performance Improvement: Super-Junction MOSFETs (SJ-MOS)
Summary of MOSFET Features by Structure
Performance of MOSFETs: Drain Current and Power Dissipation
Performance of MOSFETs: Avalanche Capability
Performance of MOSFETs: Characteristic of Capacitance
Performance of MOSFETs: Safe Operating Area(or Area of Safe Operation)
Insulated-Gate Bipolar Transistors (IGBTs)
Operation of Insulated-Gate Bipolar Transistors (IGBTs)
Performance Improvement of IGBTs: Evolution of Vertical Design
Application of IGBTs
Comparison of Forward Characteristics of IGBTs and MOSFETs
Comparison of Transistors by Structure
Datasheets of MOSFET: Maximum Ratings
Datasheets of MOSFET: Electrical Characteristics
Datasheets of MOSFET: Capacitance and Switching Characteristics
Datasheets of MOSFET: Body Diode

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