latch-up, in the four-layer device because the latch-up caused fatal device self-destruction. IGBTs had thus been established when the complete suppression of the latch-up of the parasitic thyristor was achieved. Later, Hans W. Becke and Carl F. Wheatley developed a similar device claiming non-latch-up. They patented the device in 1980, referring to it as "power MOSFET with an anode region" for which "no thyristor action occurs under any device operating conditions".

A. Nakagawa et al. invented the device