A novel lateral trench IGBT employing the p+ diverter having superior forward blocking and latch-up characteristics

A new Lateral Trench Insulated Gate Bipolar Transistor (LTIGBT) with p+ diverter was proposed to improve the characteristics of the conventional LTIGBT. The p+ divert layer was placed between anode electrode region and cathode electrode. Generally, if the LTIGBT had p+ divert region, forward blocking voltage was decreased, greatly because n-drift layer corresponding to punchthrough was decreased. However, the forward blocking voltage of the proposed LTIGBT with p+ diverter was 140 V. That 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. Because the p+ diverter region of the proposed device was enclosed trench oxide layer, the electric field moved toward trench-oxide layer. The latch-up current densities of the conventional LTIGBT and LTIGBT with p+ diverter were 540 A/cm², and 1453 A/cm², respectively. The enhanced latch-up capability of the LTEIGBT was obtained through holes in the current directly reaching the cathode via the p+ divert region and p+ cathode layer beneath n+ cathode layer