Research On Novel Lateral Integrable IGBT

The main part of the electrical energy in today's society is transformed from the non-renewable resources.Power electronics technology is a kind of technology aimed at improving the efficiency of electric energy transmission and utilization,and it can effectively help to reduce the resource consumption.Insulated Gate Bipolar Transistor?IGBT?is regarded as a milestone device in the history of power electronic device.It combines the characteristics of low driving power and fast switching speed of MOSFET and strong conductivity of bipolar device.And the process of modularization,compounding,and miniaturization of power electronic systems has promoted the research and application of Lateral IGBT?LIGBT?.However,as a bipolar device,the carrier concentration in the drift region of the traditional LIGBT is extremely high,then its turn-OFF loss(E_OFF)is significantly higher than that of the unipolar device.In addition,since the LIGBT has strong current capability,it should have excellent safety of short-circuit operation to avoid thermal breakdrown.In addition,eliminating the snap-back effect of the Reverse-Conducting IGBT?RC-IGBT?is also one of the focuses of the IGBT research.In order to improve the trade-off relationship between the E_OFF and V_ON as well as to improve the safety of short-circuit operation of the LIGBTs,and to solve the snap-back effect of RC-LIGBT,the innovative works of the thesis are included as follows:1.A SOI-LIGBT with a self-biased n-type Metal-Oxide-Semiconductor Field-Effect Transistor?nMOS?is proposed.This structure is based on the traditional trench-gate electron-injection-enhanced Silicon-On-Insulator LIGBT?SOI-LIGBT?,and Double-RESURF technology is utilized.Besides,a self-biased nMOS is introduced.The E_OFF is greatly reduced thanks to the Double Reduced Surface Field?Double-RESURF?technology.The self-biased nMOS can be turned off and on automatically during the tuning-on and off transients,and the floating state of the p-top region can also be automatically adjusted.Then,the low V_ON is realized during the ON-state and the excess carriers can be fast extracted out during the turn-OFF transient.Finally,the trade-off relationship between V_ON and E_OFF is greatly improved.The simulation results show that,under the same E_OFF,the V_ON of the structure in this thesis is 11.4%and 32.5%lower than that of the traditional Trench-Gate Electron-Injection-Enhanced SOI-LIGBT?LIEGT?and the double-RESURF LIEGT,respectively;under the same V_ON,its E_OFF is reduced by 70%and 89%compared to the latter two.2.A SOI-LIGBT with voltage-clamped diodes is proposed.Double-RESURF technology is employed in this structure to reduce the E_OFF.Besides,a heavily doped n-type carrier storage layer?n-CS?is added below the p-base region to prevent the holes from flowing into the p-base region,then the V_ON is reduced.In addition,the E_OFF of the device is further reduced by adding a SiO₂ deep trench at the anode side.Two diodes in series and a p-type shielded?p-shield?region is introduced in the structure of this thesis to eliminate the negative impact of the n-CS layer on the breakdown voltage?V_B?and to achieve a lower saturation current density.Finally,the trade-off relationship between the V_ON and the E_OFF of the new structure can be greatly optimized.In addition,a more excellent short-circuit safety operating characteristic is achieved.The simulation results show that,under the same V_ON,the E_OFF of the SOI-LIGBT in this thesis is reduced by90%and 97%compared to the traditional SOI-LIGBT and the Separated-Shorted-Anode LIGBT?SSA-LIGBT?,respectively;the maintenance time of its short-circuit safe operation is nearly three times that of the traditional SOI-LIGBT.3.A Double-RESURF SOI-LIGBT with a voltage-clamped and self-biased p-type Metal-Oxide-Semiconductor Field-Effect Transistor?pMOS?is proposed.The n-CS layer is utilized in this structure to reduce the V_ON by the prevention of the holes from being extracted by the p-base region,and Double-RESURF technology is utilized to reduce E_OFF.The self-biased pMOS introduced in this structure can help to clamp the potential of the p-shield region and the n-CS region to a low value,thereby avoiding the premature breakdown of the p-base/n-CS junction and reducing the saturation current density.In order to make the p-shield region easier to be manufactured and further reduce the hole-extrating effect by the p-base region,a deep trench is utilized at the cathode side.Finally,the trade-off relationship between the V_ON and the E_OFF of the structure in this thesis can be greatly optimized,and the short-circuit safety operating characteristic has been greatly improved.The simulation results show that,under the same E_OFF,the V_ON of the Double-RESURF SOI-LIGBT in this thesis is reduced by 15%compared with the traditional one;and its saturation current density is reduced by 50%and the maintenance time of short-circuit safe operation is increased by nearly 90%.4.An RC-LIGBT with forward and reverse parallel diodes is proposed.Reverse-parallel diode?D_R?is utilized to achieve the reverse-conduction function,and forward-parallel diode?D_F?is utilized to eliminate the snap-back effect as well as to reduce the E_OFF.In addition,compared with SSA-LIGBT and the structure composed of parallel traditional lateral PiN diode and traditional LIGBT,the new structure features a higher chip area utilization efficiency.Finally,the trade-off relationship between the V_ON and the E_OFF of this structure can be greatly optimized,and the reverse-conduction function without snap-back effect can be realized.In addition,the reverse recovery charge(Q_rr)of the structure in this thesis is lower than that of the conventional lateral PiN diode.The simulation results show that the E_OFF and Q_rr of the structure in this thesis are 44.3%and25.8%lower than that of the structure combined of the traditional lateral PiN diode and the traditional LIGBT,and its V_ON is significantly lower than that of SSA-LIGBT.