A Novel IGBT Structure With Floating N-Doped Buried Layer in P-Base to Suppress Latch-Up

The insulated-gate bipolar transistor (IGBT) has a parasitic thyristor. Latch-up can occur when the current density exceeds a particular current density. Conventional methods employed to increase the latching current density will lead to some other performance degradations. To overcome these problems and further increase the latching current density of IGBT, a novel IGBT with a floating N-doped buried layer in P-base is proposed. By implanting a floating N-doped buried layer in the P-base, the hole current flowing underneath the N+ emitter can be reduced significantly. Thus, the current density that is needed to trigger the latch-up of the parasitic thyristor increases. Numerical simulation results show that the proposed IGBT can increase the latching current density by more than 100% without compromising the output and switching characteristics when compared with the conventional IGBT.