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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