Snapback-free shorted anode LIGBT with controlled anode barrier and resistance*

Abstract

A novel shorted anode lateral-insulated gate bipolar transistor (SA LIGBT) with snapback-free characteristic is proposed and investigated. The device features a controlled barrier V _barrier and resistance R _SA in anode, named CBR LIGBT. The electron barrier is formed by the P-float/N-buffer junction, while the anode resistance includes the polysilicon layer and N-float. At forward conduction stage, the V _barrier and R _SA can be increased by adjusting the doping of the P-float and polysilicon layer, respectively, which can suppress the unipolar mode to eliminate the snapback. At turn-off stage, the low-resistance extraction path (N-buffer/P-float/polysilicon layer/N-float) can quickly extract the electrons in the N-drift, which can effectively accelerate the turn-off speed of the device. The simulation results show that at the same V _on of 1.3 V, the E _off of the CBR LIGBT is reduced by 85%, 73%, and 59.6% compared with the SSA LIGBT, conventional LIGBT, and TSA LIGBT, respectively. Additionally, at the same E _off of 1.5 mJ/cm², the CBR LIGBT achieves the lowest V _on of 1.1 V compared with the other LIGBTs.