Research On Modeling Technology For Terahertz CMOS Devices

CMOS technology has rapidly embraced the field of analog intergrated circuits,providing high-integration,low-cost,low-power consumption solutions.Accurate device model is the basis of circuit simulation design.With the development of CMOS technology,the frequency of transistor application has reached millimeter wave /terahertz frequency range.At the same time,the application frequency of the transistor model is put forward higher requirements.Therefore,the research of terahertz CMOS device model is getting more and more attention.In this thesis,the MOSFET modeling of terahertz frequency band and parameters extraction technology are studied,and a new method of de-embedding is proposed:Firstly,based on the typical physical effects in MOSFET,the MOSFET small signal equivalent circuit model is established.At the same time,in order to characterize the phase nonlinearity of S12 and S21,a new MOSFET model considering the substrate is established,and the corresponding model parameters are extracted.The calculated results are in good agreement with the experimental data,which verifies the validity of the method.Secondly,test layouts are designed,including open structure layout,short structure layout and MOSFET structure layout.At the same time,High Frequence Structure Simulator(HFSS)is used to verify open test structure and short test structure.Subsequently,a test system is established and tested in 1-220 GHz frequency range.Then,based on the physical principle and the layout structure,a complete transistor model up to 220 GHz is proposed in this thesis.The coupling model of the pad and the interconnect model are considered.The embedded structure model based on physical principle describes parasitic effects of test structure,so as to avoid the problem of embedding in terahertz band.The calculated results are in good agreement with the experimental data,which verifies the validity of the model.Finally,a new de-embedding method based on open-short circuit structure is proposed.The method is realized by the combination of model calculation and test data.Compared with the previous method,the method not only can reduce the cost,but also can realize the ultra wide frequency band de-embed.Besides,results after conventional open-short de-embedding method and proposed method are compared and analyzed.The results demonstrate the proposed method performing well from 1 GHz to 220 GHz.In this thesis,based on the test data of 90 nm CMOS process and combined with ADS simulation software,the parameters of the model are extracted,simulated and verified.