Research On IE Effect And Characteristics Of 3.3kV Trench Gate IGBT

High-voltage Insulated Gate Bipolar Transistors(IGBTs)have been widely used in rail transit and smart grid and other fields,their performance and reliability directly determine the efficiency and quality of power conversion.In this thesis,the mechanisms and characteristics of electron injection enhancement(IE)effect are analyzed by taking 3.3kV trench gate IGBT as the research object,and the avalanche effect of IGBT under overstress is studied.The main research contents are as follows:Firstly,the structure,operation principle and static、dynamic characteristics of trench-gate IGBT are analyzed,and it is pointed out that the carrier storage layer(CS)and dummy trench can be used in high-voltage IGBT to generate IE effect,which can alleviate the conflicts between saturation voltage,turn-off loss and short-circuit current,and the mechanism of IE effect in trench-gate IGBT is analyzed.The results show that the use of CS layer,wide gate and plugged dummy trench will accumulate holes under the trench gate and CS layer,resulting in an increase in the concentration of electrons inj ected by the emitter and the IE effect.Secondly,the influence of key structural parameters on the electron injection efficiency and static and dynamic characteristics of the trench-gate IGBT emitter is analyzed.The carrier concentration distribution and electron injection efficiency,as well as the blocking,conduction,switching and short-circuit characteristics of the trench gate and dummy trench gate IGBTs are compared and analyzed through simulation.The results show that using the CS layer,increasing the gate width of the trench,and plugged dummy trenches can improve the electron injection efficiency of the emitter.The maximum can reach 0.81,which makes the best compromise between saturation voltage,turn-off loss and short-circuit current;the use of separated deep P floating region can increase the breakdown voltage and reduce the rise rate du/dt of collectoremitter voltage during the turn-off process.Lastly,the reliability of trench-gate IGBTs in the terminal region under overelectric stress was studied.The static avalanche under overvoltage,the dynamic avalanche during the turn-off of overvoltage,overcurrent and short-circuit(Ⅱ)current were studied,and the generation and movement of the current filament and the lattice temperature rise inside the device were analyzed.The results show that replacing the conventional resistance region with the wave resistance region can alleviate the current stress concentration in the terminal resistance region,increase the avalanche opening voltage,and improve the device’s resistance to dynamic avalanche.The study results have certain reference value for the research and development of highvoltage IGBT devices.