A new lateral trench IGBT with p+ diverter having superior electrical characteristics

A new lateral trench insulated gate bipolar transistor (LTIGBT) with a p+ diverter was proposed to improve the characteristics of the conventional LTIGBT. The p+ divert layer was placed between the anode electrode region and cathode electrode. Generally, if the LTIGBT had a p+ divert region, the forward blocking voltage greatly decreased because the n-drift layer corresponding to the punch-through region was reduced. However, the forward blocking voltage of the proposed LTIGBT with a p+ diverter was about 140 V and the forward blocking voltage of the conventional LTIGBT of the same size was 105 V. The forward blocking voltage of LTIGBT with p+ diverter increased 1.3 times more than those of the conventional LTIGBT. As the p+ diverter region of the proposed device was an enclosed trench oxide layer, the electric field moved toward the trench-oxide layer and punch through breakdown of the LTIGBT with p+ diverter occurred. Therefore, the p+ diverter of the proposed LTIGBT did not relate to the breakdown voltage in a different way to the conventional LTIGBT. The latch-up current densities of the conventional LTIGBT and LTIGBT with p+ diverter were 540A/cm² and 1453A/cm2, respectively. The enhanced latch-up capability of the LTIGBT with a p+ diverter was obtained through holes in the current directly reaching the cathode via the p+ divert region and the p+ cathode layer beneath the n+ cathode layer