A Snapback-Free and Low Turn-Off Loss Reverse-Conducting SOI-LIGBT With Embedded Diode and MOSFET

A novel snapback-free and low turn-off loss reverse-conducting (RC) SOI-LIGBT is proposed and investigated by numerical simulations. An n-MOSFET (M
_N2
) is embedded in the anode side of the LIGBT to short the P-anode/N-buffer junction during the turn-off transient, thus allowing the LIGBT to be turned off rapidly without excessive tail current. In addition, M
_N2
enable the LIGBT to conduct the reverse conducting current like the freewheeling diode. In the forward-conducting state, M
_N2
is turned off, then the proposed LIGBT operates like a conventional one and the snap-back is avoided. The gate electrode of M
_N2
can be controlled synchronously by the gate signal of the LIGBT which is level-shifted by a p-i-n diode (D
₁
) and processed by an anode-controlling circuit, and therefore, the proposed RC-LIGBT still maintains a three-terminal configuration. D
₁
and M
_N2
are embedded in the drift region and anode-side of the LIGBT, respectively, and they can be isolated by deep-oxide trenches. The numerical simulation results reveal that the turn-off loss (
${E} _{\mathrm{ off}}$
) and reverse recovery charge of the proposed LIGBT is reduced by 58.3% and 38.9%, respectively, compared with the conventional LIGBT combining with antiparallel freewheeling diode.