Large Signal PSPICE Model For AlGaN/GaN MIS-HEMTs

AlGaN/GaN heterostructure has shown great potential in power electronics applications due to its superior characteristics such as high breakdown voltage,high density and high mobility 2-D electron gas.Especially,enhancement-mode AlGaN/GaN metal-insulator-metal high electron mobility transistors?MIS-HEMTs?,due to its extremely low gate leakage and large gate swing than Schottky or PN-junction-based HEMTs,are regarded as the next-generation power device technology.In order to accurately predict the electrical performance of AlGaN/GaN MIS-HEMT and assist in the optimization of GaN-based power electronic circuit design,this paper carried out research on GaN MIS-HEMT large-signal model,and the main research results are as follows:?1?Modeling of large-signal models was carried out around the static and dynamic characteristics of AlGaN/GaN MIS-HEMT devices.A large-signal PSPICE model of AlGaN/GaN MIS-HEMTs is proposed based on MET model.The nonlinear and non-segmented functions of the AlGaN/GaN MIS-HEMT are described using nonlinear smooth non-segmented functions.And the model parameters have a certain physical meaning,easy to extract,can be used directly to guide circuit design and device optimization.?2?Considering the threshold voltage drift caused by the gate-channel charge injection the dielectric and the semiconductor interface when the MIS-HEMT device is operating,a drain-voltage-dependent exponential threshold modulation function is introduced in the large-signal model,so that the simulation accuracy of the model static characteristics is effectively improved;At the same time,the model introduces the temperature coefficient to achieve a high degree of fitting of the measured DC data and simulation data at 25?,50? and 75?,and the root mean squared error of the DC characteristic fitting curve is less than 0.5%.?3?The dynamic model needs to contain three nonlinear capacitors:gate-source capacitor C_GS,gate-drain capacitance C_GD,and source-drain capacitance C_DS.In the modeling process,since the PSPICE simulator has no nonlinear capacitive components,this work calculates the analytical function of the nonlinear capacitance and current source through the theoretical calculation of the capacitance relation.Furthermore,the current source is used to characterize the nonlinear capacitor,which solves the simulation problem of PSPICE dynamic characteristics.By comparing the C_GD,C_GS and C_DS with the simulation curves under different working voltages,the root mean squared of the AC characteristic fitting curve is less than 0.4%,which verifies the accuracy of the model dynamic characteristics simulation.?4?Based on the ICCAP custom platform,a set of modeling and extraction procedures for the large-signal PSPICE model was established.When the model parameters are extracted,the initial values of the parameters are first obtained by using specific points in the measured data.Then optimize the parameters in the parameter extraction software ICCAP,and finally get accurate parameter values.In order to verify the convergence of the model,the built model is put into a simple switch test circuit for the time domain simulation in PSPICE.