Dynamic self-clamping at short-circuit turn-off of high-voltage IGBTs

Measurement of a complete HV IGBT I-V-characteristic up to the breakdown point

“…Also NDR (negative differential resistance) branches can be found at small gate voltages, see 10 V and 0 V behaviour in Fig. 11, which can lead to an inhomogeneous current distribution within the IGBT chip, see [5]. From this point of view, Fig.…”

“…Switching-Self-Clamping-Mode SSCM [1]) or short-circuit events with fast turn-off or Self-Turn-Off (STO) mechanisms [2] [3] [4] the IGBT is operating clearly beyond this given range. Even the breakdown branch in the I-V-characteristic can be reached, see [5]. Therefore, it would be very useful if the complete output characteristic is known.…”

TCAD simulation of current filamentation in adjacent IGBT cells under turn-on and turn-off short circuit condition

“…Therefore, γ is the product of the hole injection efficiency at p-emitter (γ PE ) and transport factor in the n-buffer layer (α T ) [1].…”

“…current filamentation) occurs, because such an effect induces strong local self-heating and restrict the turn-off capability of the switch. In previous works [1][2][3], strong collector side electric field strength (E collector ) is claimed to be one of the relevant factors for the onset of current filaments. However, cause-effect relationship between E collector and filamentation has never been completely clarified.…”

Comparison of critical current filaments in IGBT short circuit and during diode turn-off

“…Since this is approximately the breakdown voltage of the cell area of the IGBT, the destruction for high L stray is related to a clamping mode during the short-circuit turn-off (simulated e.g. in [8]). The transition from a clamping destruction (high L stray ) to a filament destruction appears at short-circuit turn-off currents of about 62 A for 300 V and 88 A for 800 V. These shortcircuit turn-off currents correlate with short-circuit currents of 63 A for 300 V and 115 A for 800 V, respectively 1 .…”