Novel Ultralow Loss SOI LIGBT With a Self-Adaptive pMOS and Double Floating Ohmic Contacts

An ultralow loss lateral insulated gate bipolar transistor (LIGBT) with improved reverse recovery characteristic is proposed and investigated by simulations. The proposed LIGBT features a self-adaptive pMOS and double floating ohmic contacts (FOC) (F1 and F2) (named as SPF LIGBT). The F1 not only controls the pMOS by providing the gate potential, but also acts as a recombination metal electrode. During turning off, in the voltage rising period, the F1 recombines the holes from the P+ anode with electrons in the N-drift region although the pMOS is in the off-state, and then in the current decreasing period, the pMOS self-adaptively turns on, and hence provides a hole current path to accelerate the recombination of electron current from N-drift region via F2. Furthermore, the turned-on pMOS also clamps the voltage drop of P+ anode/N-buffer junction to suppress the anode hole injection. Therefore, the SPF LIGBT achieves an ultrafast switching speed and low turn-off loss (E-OFF). It also can not only realize reverse conduction, but also has lower reverse recovery charge (Qrr) because the parasitic p-n-p transistor in the pMOS conducts hole current to recombine with the electrons from N-drift region through F2. Owing to the turned-on pMOS, SPF LIGBT obtains a MOS-like breakdown mode. Compared with the SSA and STA LIGBTs, the proposed LIGBT decreases the E(OFF )by 79% and 55% at the same ON-state voltage drop (V-ON). The proposed device achieves 48% lower Qrr than STA LIGBT. In short, the SPF IGBT has state-of-the-art comprehensive performance, including better V-ON-E-OFF tradeoff, higher BV and figure of merit (FOM), lower Qrr, together with reverse conduction ability.

Automated summary

An ultralow loss LIGBT model with improved reverse recovery characteristic is proposed and investigated by simulations. The model features a self-adaptive pMOS and double floating ohmic contacts (FOC) (named as SPF LIGBT). It achieves an ultrafast switching speed and low turn-off loss (E-OFF) by controlling the gate potential and acting as a recombination metal electrode.