Research On Nonlinear Circuit Model Of High Power Semiconductor Devices

As wireless communication technology develops rapidly,market demand for high-power semiconductor devices has increased dramatically.Third-generation semiconductor material GaN has attracted much attention for its excellent performance.GaN-based GaN HEMT devices have a wide application market in both civil and military fields.Successful circuit design is based on accurate and applicable device models.Small signal model and large signal model are both an indispensable part of microwave circuit design and a bridge through process,device and circuit design.In order to better apply the model to circuit design,high accuracy and low complexity of the model are the focus of researchers’research.This topic is derived from the study of Dual-Frequency Nonlinear Modeling Methods for Major Instrument Projects of the National Natural Science Foundation of China.In this paper,the high-power semiconductor device GaN HEMT device is taken as the research target of which small-signal model,large-signal I-V model and C-V model are systematically studied.After that,a complete and reliable circuit model is established.Main research contents are summarized as follows:First,based on the characteristics of device,a 19-parameter distributed model is used for small-signal modeling.Based on the 14-element model,three inter-polar parasitic capacitances are added to describe the high-frequency parasitic effects of the device.Cold-field method is used to extract parasitic parameters,and the external parasitic parameters are de-embedded to extract the intrinsic parameters.Finally,the optimization and tuning are performed in the ADS.The result shows that overall error between the simulated S-parameter and the measured S-parameter of the small-signal model is 4.375%in the range of 1 GHz to 6 GHz.Then,large signal I-V and C-V large signal models are studied.GaN HEMT devices have obvious self-heating effects.However,single(1+λV_ds)term of the traditional Angelov I-V model does not accurately characterize saturation region of the I-V characteristics.Therefore,a self-heating network is added to the large-signal model,which improves the fitting accuracy of saturation region of the I-V curve.In addition,parameters I_pk and P₁ are modified to characterize their relationship with drain-source voltage V_ds,which improves the fitting accuracy of linear and saturated regions.The result shows that root mean square error between the model and the measured I-V data is 2.1%.Thus,fitting accuracy is much higher than the traditional method.Then,gate-source capacitance C_gs expression in the traditional Angelov C-V model is improved.Parameters B₀ and B₁ are added to describe the rising trend of C_gs in the high V_ds region.gate-source capacitance C_gs and gate-drain capacitance C_gd are successfully modeled.Finally,an AB-type power amplifier operating at 3 GHz is designed using circuit model simulation in ADS.An complete process of power amplifier design is given.The result shows that the power amplifier has an output power of approximately 40.5 dBm,a gain of approximately 14.5 dB,and a PAE of approximately 66.9%.