Establishment And Verification Of AlGaN/GaN HEMT Device Model

AlGaN/GaN HEMT device has high operating frequency,high power density,high temperature resistance,good linearity,easy matching and high input impedance,which is widely used in monolithic microwave integrated circuits?MMIC?.The Research and development personnel in the design of microwave integrated circuits using suitable Ga N HEMT device model for simulation and design of MMIC,which reduces the development costs,the success rate of the design has been greatly improved,but also shorten the development cycle,so accurate AlGaN/GaN HEMT model is very important for designing microwave integrated circuit.Based on the AlGaN/GaN HEMT device,this paper studies the small signal equivalent circuit model and the large signal equivalent circuit model.The main contents are as follows:According to the needs of this study,select the appropriate AlGaN/GaN HEMT device,the final choice of the device type is AM005WN-BI-R.In order to measure the S-parameters of the device to facilitate the follow-up work,I designed a test fixture and a TRL calibrator,and measured the S-parameters of the device with 1-6GHz at different Bias voltage using the vector network analyzer.For the small-signal equivalent circuit model of the traditional 14 components,the structure is simple,the model parameters are few,and get the model parameters are easy,but the model are not considered the dispersion effect at high frequency for AlGa N/GaN HEMT devices,the precision of the model is not high enough.And The model of the small signal equivalent circuit of 22 model parameters considering some parasitic effects of the device at high frequencies,and the model has high accuracy,however,the equivalent circuit model is complex and the model parameters are difficult to get.This paper uses a small signal equivalent circuit model of 18 components,which is based on the14-component small-signal equivalent circuit model,taking into account the influence of the parasitic capacitance between the electrodes on the electrical characteristics of AlGaN/GaN HEMT devices under high frequency,the model accuracy is higher and the extraction of model parameters is relatively easy.Based on the measured S-parameter of the GaN HEMT device,I extract the parasitic parameters of the small signal model and then extract the intrinsic parameters by the method of de-embedding.Finally,the model and model parameters are validated in ADS.The specific approach is:Firstly,the parasitic capacitance of the model is extracted by using the S-parameter of the device in the cut-off state,and the parasitic resistance and parasitic inductance of the model are extracted by using the S-parameter of the device in the zero-bias state.Then the intrinsic parameters of the model are obtained by the mutual transformation between the S-parameter,the Y-parameter and the Z-parameter using the S-parameter of the device under normal operation.Finally,setting up the equivalent circuit of the small signal model in ADS,by comparing the S-parameters obtained by the measurement and by the simulation,it is verified that the small signal equivalent circuit model and model parameters adopted in this paper have high precision.Based on the analysis of several classical large signal equivalent circuit models,the EEHEMT large signal equivalent circuit model is adopted in this paper,which considers the self-heating effect under the large signal and high frequency dispersion effect of the GaN HEMT devices and the model precision is high.Based on the S-parameters measured under different Bias voltage and the small-signal model parameters,I extracted the large signal model parameters by fitting the g_m^V_gs curve and the C_gs^V_gs curve and combining the characteristics of the EEHEMT large signal model.In order to verify the EEHEMT large signal model and model parameters,I set up the artificial circuit in ADS,and the accuracy of the EEHEMT large signal model and model parameters is verified by comparing the measured S-parameters with the simulated S-parameters.