Research On Mechanism And New Structures About Negative Differential Regime In SOI SA-LIGBT

Conventional shorted anode lateral insulated-gate bipolar transistor(SA-LIGBT)on silicon-on-insulator(SOI)has advantage of high turn-off speed,and the structure also has disadvantage of negative differential resistance regime(NDR).The NDR regime causes high power cons?mption,low transconductance and bad linearity.To suppress the NDR regime,we analyzed mechanism of NDR in SA-LIGBT firstly and then proposed two new LIGBT structures.The simulation results are as follows:(1)A P-Buired-Layer Anode side lateral insulated-gate bipolar transistor(PBLA-LIGBT)is proposed.Compared to conventional SA-LIGBT,PBLA-LIGBT structure has a new P-type charge region.The P charge region help to increase the length of electronic current path or decrease the width of N channel,then,the resistance Rp under the anode P+ is significantly increased,which effectively suppresses the NDR regime.In this paper,we also discussed about I-V,blocking and turn-off characteristics.Simulation results show that the blocking voltage of PBLA-LIGBT is increased to 226 V,at the same time,the turn-off time do not degenerate and the NDR is suppressed.This structure also simplify fabrication process and then low process cost.(2)An anode weak inversion layer lateral insulated-gate bipolar transistor(AWIL-LIGBT)is proposed.In this structure,an inversion layer is added at the anode side of conventional SA-LIGBT.The distinguishing feature of new structure is that a high resistance area is introduced by weak inversion layer,which can conduct the P+/N-buffer junction under the condition of lower majority carrier and then the NDR is suppressed.Simulation results show that the turn-off speed doesn't deteriorate and the blocking voltage increases up to 111V(approximately 56%)without NDR regime after comparing with the conventional SA-LIGBT.