The Effect Of Radiation On The Characteristics Of 1200V IGBT

Insulated Gate Bipolar Transistor(IGBT)combines power MOS(Metal-Oxide-Semiconductor)and bipolar junction transistor(BJT)with the characteristics of voltage control and low on-resistance.With the advancement of atomic energy technology,IGBTs may also be used in radiation environments such as nuclear reactors.As the power control device of nuclear reactor control rod drive mechanism,the importance of rod control system is self-evident.In recent years,due to the characteristics of voltage control and high operating frequency of IGBT devices,domestic and foreign manufacturers have begun to use IGBTs in rod control systems.The nuclear fission reaction emits neutrons and gamma rays,which make the electronic equipment around the nuclear reactor suffer from both neutron radiation and total ionizing dose(TID)effects.However,the mechanism of radiation effect of IGBT in the coexistence of TID and neutron is not very clear.Based on this,this thesis studies the mixed radiation effect of IGBT devices,and expounds the mechanism of mixed radiation effect of IGBT devices.The main contents of this thesis are as follows:(1)The experiment of single TID is carried out,the effect of single TID on the static characteristics of IGBT devices is analyzed,and the mechanism of TID is revealed through simulation.Due to the introduction of the fixed positive charge in the oxide layer and the interface state at the Si/Si O₂ interface by TID,the threshold voltage of the IGBT device decreases,the breakdown voltage decreases,and blocking-state leakage current in the cell region increases.The effect of single neutron radiation on the electrical characteristics of IGBT devices is studied,including transfer characteristics,blocking characteristics,conduction characteristics and switching characteristics.Single neutron radiation reduces the lifetime of minority carrier,which increases the breakdown voltage,the on-state voltage drop of the device and the leakage current of blocking state,reduces turn-off time.(2)The effects of mixed radiation on the transfer characteristics,blocking characteristics,conduction characteristics and switching characteristics of IGBT devices are analyzed by simulation,focusing on the differences of electrical characteristics of IGBT between mixed radiation and single radiation.Under the mixed radiation,the neutron radiation reduces the current gain of the PNP transistor,thereby reducing the leakage current caused by interface state.TID makes the depletion region shrink and the width of the neutral base region increases,thereby reducing the current gain of the PNP transistor,resulting in the breakdown voltage of the junction terminal region is not sensitive to neutron radiation.