InP HBT High Frequency Equivalent Circuit Modelling Based On Electromagnetic Assisted Simulation

Indium phosphide-based heterojunction bipolar transistors(InP HBTs)have good high-frequency characteristics and noise performance,and have great potential for circuit design in the millimeterwave terahertz band.The device model is the bridge between the physical structure of the device and the circuit design,and an accurate device model is the key to characterize the performance of the circuit design.As the semiconductor industry continues to evolve,the required operating frequencies are increasing and parasitic effects on high frequency high power devices are becoming more significant.The parasitic parameters of the conventional InP HBT equivalent circuit model are not fully characterized and cannot be applied to the operating frequency requirements above the W-band.In this paper,we focus on the modeling of InP HBT high-frequency equivalent circuit model based on electromagnetic-assisted simulation method and the improvement of dispersion effect of Agilent HBT large-signal model,which are mainly studied as follows.First,for the traditional InP HBT high-frequency equivalent circuit model,the parasitic parameters are not fully characterized and can only be applied to W-band and below.In this paper,the electromagnetic three-dimensional structure and parasitic parameters of the InP HBT are modeled by electromagneticassisted simulation.The scattering parameters obtained based on the electromagnetic 3D structure of the InP HBT are used to extract the parameter values of the parasitic parameter model,which ensures the accuracy of the extraction of the device intrinsic parameters.The proposed parasitic parameter model has a complete parasitic parameter structure and a clear physical meaning.Secondly,the InP HBT small-signal equivalent circuit modeling and large-signal equivalent circuit modeling are completed based on the proposed parasitic parameter model.After de-embedding the parasitic parameters,the eigenparameters of the InP HBT small-signal equivalent circuit model are extracted using the direct extraction method.Since the InP HBT large-signal model has nonlinear characteristics,the eigenparameters of the InP HBT large-signal equivalent circuit model are extracted using the empirical formula method.For the problem that the existing Agilent HBT large-signal model cannot describe the device dispersion effect.In this paper,the dispersion effect is improved by adding the RF current source branch.The results show that the improved Agilent HBT model corrects the inconsistency between the RF and DC transconductance of the device and can operate at frequencies above the W band.Finally,the proposed InP HBT high-frequency equivalent circuit model is verified.The small-signal and large-signal high-frequency equivalent circuit models of the InP HBT are embedded into the ADS2016 software to obtain the simulated scattering parameters.The experimental results show that the simulated scattering parameters of the InP HBT small-signal and large-signal high-frequency equivalent circuit models are consistent with the measured scattering parameters in the literature,which verifies the validity of the proposed models.Meanwhile,the proposed model has good stability in the frequency band of 0-325 GHz.