Shield-gate-trench Power MOSFET Simulation And SPICE Model Research

Different from the traditional VDMOS and trench MOS devices,power Shield Gate Trench MOSFETs incorporate a polysilicon shield gate below the gate in the trench and at the same potential as the source,and introduced the horizontal depletion layer on the basis of the vertical depletion layer,which can obtain an approximate trapezoidal electric field distribution.Therefore,while ensuring the small conduction resistance of the device through doping,better breakdown characteristics can be obtained.At the same time,the shield can reduce the miller capacitance and improve the switching performance of the device.Therefore,SGT-MOSFET has obvious competitiveness in low and medium voltage field.Widely used in many fields such as Power management,motor drive,DC/DC and AC/DC subsystem current Switching,Load Switching,Quick/Wireless Charging,etc.Device model as a bridge between process and simulation design,SGT-MOSFET device modeling in China is not yet a set of mature processes and methods,to establish a model for SGT-MOSFET devices and modeling methods flow is particularly important.This paper first uses TCAD to simulate the structure and performance of SGT-MOSFET devices and analyze the mechanism of their operating behavior and then obtain simulation data.A device with off-state breakdown voltage of 85V and conduction resistance of 9m?(V_GS=7V)is obtained.Due to the different methodological strategies for modeling the temperature compensation model and the capacitance model in the HSPICE simulator and the PSPICE simulator,the SPICE MODEL modelling of SGT-MOSFETs was carried out on the basis of these two commonly used simulators,respectively,and an accurate macro model with wide voltage range is proposed,and based on the HSPICE simulator,a modeling method for the drain-source capacitor subcircuit model of power devices is proposed.This model is mainly composed of CORE MOSFET,diode,capacitor and resistance.It can accurately simulate the DC and AC characteristics of SGT-MOSFET.Moreover,this macro model is composed of simple devices and has good applicability with various EDA simulation software.The SGT-MOSFET model established in this paper has high simulation speed,accuracy and flexibility.The model has been demonstrated with dozens of sets of actual test data for SGT-MOSFET devices in the voltage withstand range of tens to150 volts.The(RMS)between model simulation results and actual test data is within5%,which meets the requirements of the industry.At the same time,a complete SGT-MOSFET device modeling process was established,including a complete set of modeling methods including data processing,model establishment,parameter extraction modeling,and result verification,and completed the expected goals of the thesis.