| Insulated gate bipolar transistor(IGBT)has been widely used in the field of power electronics due to its low conduction voltage drop,high current density,high input impedance and wide safe working area.Trench gate IGBT has become the mainstream in the motor drive system due to its lower on-voltage drop and better switching characteristics.However,the traditional trench IGBT device brings a large di/dt in the high-speed switching process,which affects gate controllability when it is turned on.This paper aims to optimize and analyze the traditional trench IGBT and design a trench IGBT device with low on-voltage drop and high gate controllability.In this thesis,the basic working principle of the trench IGBT device is analyzed in detail firstly,and the internal mechanism of the turn-on voltage drop characteristics and gate controllability of trench IGBT devices is explained.The optimization ideas for reducing the number of accumulated holes and reducing the gate charging capacitance are proposed.Then,based on the idea of reducing the number of accumulated holes,a trench IGBT device with a deep floating P layer and a trench IGBT device with a floating trench emitter are designed and verified by simulation;based on the idea of reducing the gate charge capacitance,a trench IGBT device with trench shield emitter is designed and verified by simulation.Finally,a comprehensive comparative analysis of the three new structures shows that the trench IGBT device with trench emitter protection is the optimal structure.The simulation results show that the breakdown voltage of trench IGBT with trench shield emitter is 1630V,the threshold voltage is 5.0V,the on-voltage drop is 1.46V at the current density of200A/cm~2;under the condition of low current turn-on,the current change rate is 650A/?s,which is an increase of 18%compared with traditional trench IGBT devices,and the di/dt is highly sensitive to the gate resistance R_G.All of the performance parameters meet the design specification. |
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