Research On New Structure Of 600V Low Loss Trench IGBT Devices

In the medium and high power field,IGBT is widely used in various frequency conversion and speed control systems due to its excellent performance.And it has become one of the most popular power semiconductor devices in the fields of new energy vehicles,motor control,air conditioning,locomotive traction,high voltage direct current transmission etc..In recent years,with the development of IGBT technology,there is an urgent need for high power density and low loss devices.In this thesis,two novel low-loss IGBTs are proposed based on the conventional trench IGBT structures,which can not only improve the tradeoff relationship between the on-state voltage drop(V_CEON)and turn-off energy loss(E_OFF),but also improve the tradeoff relationship between the dV_AK/dt of the Free-wheeling Diode?FWD?during reverse recovery period and the IGBT turn-on energy loss(E_ON).1.A novel DSG-FP IGBT?Dual split gate IGBT with floating p-well?structure features dual split gate trench IGBT with floating p-well is proposed.The new structure introduces two split electrodes that connected with the emitter in the trench.On the one hand,the effect of displacement current I_dis that produced by floating p-base region during the turn-on period on the gate current I_G is avoided,which can reduce the Electromagnetic Interfarence?EMI?effect in the circuit.On the other hand,the Miller capacitance(C_GC)of the new device is reduced.Besides,the effect of carrier stored?CS?layer doping on the breakdown voltage?BV?is avoided by adopting thicker oxide layer in the bottom of the trench.So that the new structure has higher BV compared with the conventional structure,thus the on-state voltage drop V_CEON is reduced.Finally,the Miller capacitor C_GC of the new structure drops 97.9%compared to the conventional structure.And the turn-off energy loss E_OFF of the new structure is 64.3%lower than that of the conventional structure under the same V_CEON.The turn-on energy loss E_ON of the new structure reduces 38.2%compared to the conventional structure under the same dV_AK/dt of the FWD during reverse recovery.And the dV_AK/dt of the new structure is45.9%lower than that of the conventional structure under the same E_ON.2.A novel SGRET IGBT?Split gate recessed emitter trench IGBT?structure features split gate trench IGBT is proposed.The split gate structure reduces the Miller capacitance C_GC.And on the other hand,the thicker oxide layer in the bottom of the trench structure makes the SGRET IGBT structure has higher BV compared to the conventional structure,thus reducing the on-state voltage drop V_CEON.As a result,the Miller capacitor C_GC of the new structure drops 84.3%compared to the conventional structure.And the turn-off loss E_OFF of the new structure is 67.0%lower than that of the conventional structure at the same V_CEON.And the dV_AK/dt of the new structure reduces24.5%compared to the conventional structure at the same E_ON.The turn-on energy loss E_ON of the new structure reduces 17.0%compared to the conventional structure under the same dV_AK/dt of the FWD during reverse recovery.3.The process design for the DSG-FP IGBT structure is proposed.Firstly,the cell that meets the basic requests for the breakdown voltage,the on-state voltage drop and the threshold voltage is designed,and the influence of epitaxial layer parameters,P body region parameters,CS layer parameters and Field stop?FS?layer parameters are simulated.Secondly,a terminal structure with field limiting ring?FLR?and field plate?FP?to meet the requests of breakdown voltage and reliability is designed,and the characteristics of electric field distribution,potential distribution and current path during breakdown are analyzed.Finally,the layout design of DSG-FP IGBT structure is completed.