Editing Integrated gate-commutated thyristor (section)

== Device description ==
[[File:GCT wafer.svg|alt=|thumb|Top view of a typical 91mm wafer Gate Commutated Thyristor with cathode segments arranged in 10 concentric rings and the gate contact placed between Ring 5 and Ring 6 <ref name=":0">{{Cite journal|last=Neophytos|first=Lophitis|date=2014|title=Novel and conventional gate commutated thyristors : modelling and analysis|url=https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648845}}</ref>]]
[[File:1 GCT cut.svg|thumb|Gate Commutated Thyristor (GCT) typical device structure and doping<ref name=":0" />]]
An IGCT is a special type of [[thyristor]]. It is made of the integration of the gate unit with the Gate Commutated Thyristor (GCT) wafer device. The close integration of the gate unit with the wafer device ensures fast commutation of the conduction current from the cathode to the gate. The wafer device is similar to a [[gate turn-off thyristor]] (GTO). They can be turned on and off by a [[gate signal]], and withstand higher rates of voltage rise (dv/dt), such that no [[snubber]] is required for most applications.

The structure of an IGCT is very similar to a GTO thyristor. In an IGCT, the gate turn-off current is greater than the anode current. This results in a complete elimination of minority carrier injection from the lower PN junction and faster turn-off times. The main differences are a reduction in cell size, and a much more substantial gate connection with much lower inductance in the gate drive circuit and drive circuit connection. The very high gate currents and fast dI/dt rise of the gate current mean that regular wires can not be used to connect the gate drive to the IGCT. The drive circuit [[printed circuit board|PCB]] is integrated into the package of the device.  The drive circuit surrounds the device and a large circular conductor attaching to the edge of the IGCT is used. The large contact area and short distance reduce both the inductance and resistance of the connection.

The IGCT's much faster turn-off times compared to the GTO's allows it to operate at higher frequencies—up to several kHz for very short periods of time. However, because of high {{ill|switching loss|lt=switching losses|de|Schaltverluste}}, typical operating frequency is up to 500&nbsp;Hz.

Neutron-Transmutation-Doped Silicon used as the IGCT base substrate.<ref name="Eicher et al., 2000">{{Cite book|last1=Eicher|first1=S.|volume=5|pages=2859–2865|last2=S. Bernet, P. Steimer, A. Weber|title=Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129) |chapter=The 10 kV IGCT-a new device for medium voltage drives |doi=10.1109/IAS.2000.882571|year=2000|isbn=0-7803-6401-5 |s2cid=109030444 }}</ref>

IGCTs, in high power applications, are sensitive to cosmic rays. To decrease cosmic ray induced malfunctions, more thickness in the n<sup>−</sup> base is required.<ref name="Eicher et al., 2000" />