Lateral trench IGBT with effective p/sup +/ diverter having superior electrical characteristics for smart power IC

摘要

A new lateral trench insulated gate bipolar transistor (LTIGBT) with p/sup +/ diverter was proposed to improve the characteristics of the conventional LTIGBT. The p/sup +/ divert layer was placed between anode electrode region and cathode electrode. Generally, if the LTIGBT had p/sup +/ divert region, forward blocking voltage was decreased greatly because n-drift layer corresponding to punch-through was decreased, However, the forward blocking voltage of the proposed LTIGBT with p/sup +/ diverter was 140 V. That of the conventional LTIGBT of the same size was 105 V. The forward blocking voltage of LTIGBT with p/sup +/ diverter increased 1.3 times more than those of the conventional LTIGBT. Because the p/sup +/ diverter region of the proposed device was an enclosed trench oxide layer, the electric field moved toward trench-oxide layer, and punch through breakdown of LTIGBT with p/sup +/ diverter occurred. Therefore, the p/sup +/ diverter of the proposed LTIGBT didn't relate to breakdown voltage in a different way to conventional LTIGBT. The latch-up current densities of the conventional LTIGBT and LTIGBT with p/sup +/ diverter were 540A/cm/sup 2/, and 1453A/cm/sup 2/, respectively. The enhanced latch-up capability of the LTEIGBT was obtained through holes in the current directly reaching the cathode via the p/sup +/ divert region and p/sup +/ cathode layer beneath n/sup +/ cathode layer.