Study On New Structure Of Trench-gate SOI-LIGBT Devices With Self-biased P-type Buried Layer

With its advantages of high power and integration,the lateral insulated gate bipolar transistor based on silicon-on-insulator material（SOI-LIGBT）is playing an increasing role in power integrated circuit systems.The reduced surface field（RESURF）technology can improve conduction performance while ensuring the breakdown voltage（BV）of the device.For the conventional SOI-LIGBT with RESURF structure（CON-LIGBT）,the connection of the P-type top（P-top）layer to the P-type emitter region accelerates the extraction of holes in the drift region during the turn-off state,which weaks the conductance modulation level in the drift region during the forward conduction.In order to solve the above problem,based on the CON-LIGBT,the thesis proposes two new SOI-LIGBT structures.And focusing on the on-state voltage(V_CEON),the turn-off loss(E_OFF),the saturation current density(J_sat),the threshold voltage(V_th)and other key performance parameters,the new structures are simulated and optimized.1.A new structure of trench-gate SOI-LIGBT with self-biased P-type buried layer（SPB-LIGBT）is proposed.Based on the CON-LIGBT,the new structure introduces the emitter trench structure,the N-type buried layer（buried-N layer）and the self-biased P-type buried layer（P-base（Ⅱ）layer）,which form two PMOS structures.When the device is forward-conducting,the potential of the P-type buried layer is low,the two PMOS structures are turned off,and the buried-N layer will prevent holes in the drift region from being extracting by the emitter,which reduces the V_CEON.When the device is turned off,the potential of the P-type buried layer increases and the two PMOS structures are turned on,the holes in the drift region gain extraction paths,which reduces the E_OFF of the device.The simulation results show that the V_CEON of the SPB-LIGBT is 1.17V at the collector current density（J_C）=200A/cm²,which is 30.4%and 12.0%lower than that of the CON-LIGBT ane the CS-LIGBT,respectively.When the V_CEON is the same 1.14V,the E_OFFof the SPB-LIGBT is 77.6%and 71.6%lower than that of CON-LIGBT and CS-LIGBT,respectively.In addition,the total gate charge（Q_G）of the new structure is 9.3%and 10.8%lower than that of CON-LIGBT and CS-LIGBT,respectively,and its miller plateau charge(Q_GC)is 25.4%and 27.4%lower than that of CON-LIGBT and CS-LIGBT,respectively.2.In order to improve the relationship between the J_sat,the V_th and the V_CEON in the SPB-LIGBT,a new structure of three-dimensional trench-gate SOI-LIGBT with partial self-biased P-type buried layer（PSPB-LIGBT）is further proposed,and two implementation schemes（PSPB-LIGBT-1 and PSPB-LIGBT-2）are discussed.The design of the partial P-type buried layer in the two variant structures can ensure that the V_th is not affected.The high concentration P-type buried layer can reduce the J_sat,but a part of the V_CEON will be lost.The simulation results show that the V_th of the PSPB-LIGBT-1 and the PSPB-LIGBT-2 is 2.96V,which is not affected by the P-type buried layer.The J_sat of the PSPB-LIGBT-1 and the PSPB-LIGBT-2 is 28.3%and 41.4%lower than that of the 3D-SPB-LIGBT,and the short circuit withstand time(t _SC)of the PSPB-LIGBT-1 and the PSPB-LIGBT-2 is 85.7%and 121.4%higher than that of the 3D-SPB-LIGBT.Meanwhile,the PSPB-LIGBT-1 and the PSPB-LIGBT-2 sacrifices a portion of V_CEON,and their V_CEON is only 21.2%and 24.6%higher than that of the 3D-SPB-LIGBT,respectively.