Turn-off Mechanism And Characteristics Analysis Of Mos-gct

Integrated Gate Commutation Thyristor(IGCT)uses a "hard drive" technology to control its turn-on and turn-off.The gate control unit needs to provide a high rising rate and large amplitude current pulse,which requires a very low inductance and resistance between the GCT and the gate drive units,so GCT and gate drive circuits are usually integrated in one printed circuit board,but this makes the IGCT drive circuit complex,bulky and reduced flexibility.To solve the above problems of IGCT,this paper proposes a Dual Gate MOS-GCT which integrates the pMOS transistor in turn-off circuit directly on the GCT chip and uses the negative gate voltage to control turn-on of pMOS to achieve internal instantaneous commutation to simplify the drive circuit.Taking the blocking voltage of 3.3kV as an example,the switch mechanism of the Dual Gate MOS-GCT is studied by Sentaurus-TCAD simulator.The characteristics are simulated,and the influences of the key structural parameters and high temperature on the device characteristics are analyzed.Finally,the working mechanism and characteristics of an integrated MOS-GCT are studied.The main research contents are as follows:Firstly,the structure,working principle and process characteristics of Dual Gate MOS-GCT are analyzed,the process of chip fabrication is determined,and the process simulation is carried out.The structure model and dynamic characteristic test circuit are set up.By analyzing the change of electric field intensity,carrier concentration distribution and current density during the turn-off process,the turn-off mechanism of Dual Gate MOS-GCT is studied.Research shows that Dual Gate MOS-GCT can realize internal commutation.Secondly,the static and dynamic characteristics of Dual Gate MOS-GCT are studied.The key structural parameters,such as the structural parameters of the Integrated pMOS,the n-base area,the p base area and the width of the n+ cathode area on the various characteristics of the device are analyzed,and the reasonable structural parameters are extracted.The effect of temperature on the characteristics of the device is compared and analyzed.Thirdly,an Integrated MOS-GCT is studied,which combines the turn-on gate(Gon)and the turn-off gate(Goff)of Dual Gate MOS-GCT.The structural features and process methods of Integrated MOS-GCT are analyzed,and the blocking mechanism and switching mechanism of Integrated MOS-GCT are studied,and the characteristics of Dual Gate MOS-GCT are compared.The results show t he integrated gate MOS-GCT is slightly less than Dual Gate MOS-GCT in switching characteristics,but it can be driven completely by voltage,thus further simplifying the drive circuit and packaging structure.The research results in this paper have some reference value for the design and development of IGCT.