| As one of the mainstream switching devices with medium to high power,Insulated Gate Bipolar Transistor(IGBT)has been widely used in new energy fields due to its high power density,low loss,high reliability,and other advantages.By adopting a superjunction drift region structure,superjunction IGBT has extremely excellent electrical characteristics,and has become one of the research hotspots of IGBT in recent years.However,due to the complex physical mechanism of superjunction IGBTs,the conductivity modulation in the drift region(especially when using medium and low column concentrations)is still not optimized,limiting further improvement in device performance and reliability.In order to further improve the performance of superjunction IGBT,this thesis has conducted in-depth research on the new structure of conductivity modulation enhanced superjunction IGBT.The main work is as follows:1.A new structure of narrow mesa floating P-region superjunction IGBT(NMFP-SJIGBT)is proposed.The proposed structure achieves a dual carrier injection enhancement structure by introducing narrow mesa and floating P-region on the device surface,enabling the device to achieve a strong conductivity modulation effect over a wide column concentration range,while achieving good electrical characteristics and improving process tolerance.The simulation result show that when column concentration range in 1×1014cm--3 to 1×1016cm-3,the conduction voltage drop(Vceon)of NMFP-SJIGBT at a conduction current density of Jce=100 A/cm2 remains basically unchanged.Compared to conventional SJ-IGBTs(CON-SJ-IGBT),superjunction IGBTs with N-type carrier injection layers(NI-FP-SJ-IGBT),and superjunction IGBTs with gate isolated floating P-columns(GFP-SJ-IGBT),the Vceon of NMFP-SJ-IGBT is at 1×10-4cm-3 concentration,it decreased by 51.9%,50.2%,and 31.8%,respectively.While at 1 ×1015cm3 it is decreased by 74.5%,39.6%,and 26.2%,respectively.When Vceon is both 1.05V,the column concentration is all 1 ×1015cm-3,the turn-off loss(Eoff)of NMFP-SJ-IGBT is much better than that of CON-SJ-IGBT,and is reduced by 73.7%and 35.4%compared to NIFP-SJ-IGBT and GFP-SJ-IGBT,respectively.The Vceon-Eoff tradeoff characteristic is significantly improved.2.On the basis of NMFP-SJ-IGBT,a new conductivity modulation enhanced superjunction IGBT structure with a dual gate structure is proposed.By introducing a trench gate connected to the emitter between the gate and the floating P region,the problems of large switching delay and poor capacitive charge characteristics in a single gate structure are solved,while further improving the Vceon-Off compromise characteristics,switching characteristics,and EMI resistance capabilities.The simulation results show that compared to CON-SJ-IGBT,NI-FP-SJ-IGBT,GFP-SJ-IGBT,and single gate NMFP structures,the gate collector capacitance of dual gate NMFP-SJ-IGBT decreases by 55.1%,68.1%,81.3%,and 84.4%,respectively;The gate charges decreased by 44.3%,44.3%,77.1%,and 79.2%,respectively.The turn-off loss of the dual gate NMFP-SJ-IGBT is reduced by 29.4%compared to the single gate NMFP structure when the Vceon is 1.02V and the column concentration is 1×1015cm-3.In addition,at a turn-on loss of 8.7mJ/cm2,the dV/dt of the dual gate NMFP structure is 26.9%lower than that of the single gate NMFP structure... |
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