Analysis And Optimization Of High Speed And Low Loss SOI RC-LIGBT

Lateral insulated gate bipolar transistor(LIGBT)is widely used in the field of power integrated circuits because of its simple driving circuit,strong current capability and strong compatibility with IC process.Reverse conducting LIGBT(RC-LIGBT)integrates a free wheeling diode(FWD)in reverse parallel,so it has reverse conducting ability.For RC-LIGBT,eliminating Snapback phenomenon and improving the tradeoff between forward conduction voltage(V_CEON)and turn off loss(E_OFF)has always been a research hotspot.Based on this,two kinds of SOI RC-LIGBT device structures are proposed.1.An SOI RC-LIGBT with p-type buried layer(PBL RC-LIGBT)is proposed.The p-type buried layer introduced in the device structure can block the electrons below it to a certain extent,thus increasing the distribution resistance of the anode region of the device,so that the Snapback phenomenon can be eliminated and the additional device area will not be occupied.At the same time,because of the super junction LDMOS structure on its surface,the V_CEON of the device can be reduced and the device has reverse conduction ability.Compared with SSA-LIGBT,the V_CEON of PBL RC-LIGBT is reduced by 49.46%,and the reverse conduction voltage(V_R-CEON)is reduced by 29.8%.Under the same V_CEON,the E_OFF of PBL RC-LIGBT is 76.6%lower than that of traditional LIGBT,and 91.9%less than that of SSA-LIGBT.Moreover,the turn off time(t _OFF)of PBL RC-LIGBT is 55.9%lower than that of traditional LIGBT and 86.9%lower than that of SSA-LIGBT.However,after the conductance modulation effect occurs in the drift region,high concentration carriers can pass through the p-type buried layer,which limits the further improvement of device performance to a certain extent.2.An SOI RC-LIGBT(DBL RC-LIGBT)with dielectric buried layer is proposed.In order to overcome the shortcomings of PBL RC-LIGBT,a dielectric buried layer is introduced in DBL RC-LIGBT to form better electrical isolation between the super junction LDMOS above dielectric buried layer and the LIGBT below dielectric buried layer.The simulation results show that the V_CEON of DBL RC-LIGBT is 31.3%lower than that of traditional LIGBT,71.4%lower than that of SSA-LIGBT,and 43.5%lower than that of PBL RC-LIGBT.The V_R-CEON of DBL RC-LIGBT decreased by 20.6%compared with SSA-LIGBT,and increased by 13.1%compared with PBL RC-LIGBT.Compared with the traditional LIGBT,the E_OFF and t _OFF of DBL RC-LIGBT are reduced by 90.5%and 77.1%respectively under the same V_CEON.