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Investigations of avalanche dynamics in IGBTs, bipolar GTOs and MCTs

Publication Type:

Conference Paper

Source:

Proc. of Telecommunications Energy Conference, 1995. INTELEC '95., 17th International , 29 Oct.-1 Nov. 1995, The Hague, The Netherlands, The Hague, Netherlands, p.340 - 345 (1995)

URL:

http://ieeexplore.ieee.org/search/srchabstract.jsp?arnumber=498973&isnumber=10697&punumber=3585&k2dockey=498973

Keywords:

MOS-controlled thyristors avalanche breakdown bipolar transistor switches insulated gate bipolar transistors p-n heterojunctions power bipolar transistors power semiconductor switches semiconductor device models thyristors IGBT MCT MOS controlled thyristo

Abstract:

A comprehensive investigation of the dynamic avalanche breakdown in
insulated gate bipolar transistors (IGBT), bipolar gate turn off
(GTO) thyristors and MOS controlled thyristors (MCT) is performed
in this work. Based on analytical models of the failure mechanism
due to dynamic avalanche, straightforward expressions of the effective
dynamic forward blocking voltage fairly correctly predicting the
decrease of sustaining voltage are deduced in this work. For the
IGBT, two types of dynamic avalanche breakdown are identified: one
during the unipolar phase of turn off; the second during the bipolar
phase of the transient turn off. It is shown that for a gain of the
active inner bipolar transistor less than 0.5, dynamic avalanche
breakdown occurs only in the bipolar phase of turn off. The reduction
of the gain below 0.4 greatly diminishes the chances for the dynamic
breakdown of IGBTs. The phenomena leading to the dynamic avalanche
breakdown of bipolar GTOs and MCTs with PMOS type turn off gate are
rather similar. The design and drive conditions that might eliminate
the dynamic avalanche breakdown are also presented in this work