Equivalent Circuit Modeling Of Nanoscale MOSFET In Millimeter-wave Range

With the development of down-scaling of CMOS technology for low power,mixed-signal,and high frequency applications,the optimal high freq uency performance is shifted from moderate toward weak inversion regimes.Small-signal equivalent circuit model and parameter extraction method is a prerequisite for designing the radio frequency and millimeter-wave circuits,and is essential for the noise analysis of nanoscale metal-oxide-semiconductor field-effect transistors(MOSFETs).Although a lot of effort has already be en put into characterizing and modeling the MOS transistor at RF,most of the published work in the literature is focused either on the high-performance SI region or on more mature processes with respect to the state-of-the-art or the modeling part is not expressed in consistency with the standard compact MOSFET models.Such models can describe the device characteristics accurately in each region,but cannot guarantee the continuities of the model at the transition point from one region to another.Based on the physical structure of the device,a compact and accurate quasi-static small-signal MOS transistor equivalent circuit for millimeter-wave frequency applications and an efficient direct extraction method have been developed which provide an effective way to model and predict the millimeter-wave frequency characteristics of MOS transistors.The simplified equations for the Y-parameters can be used to derive the expressions for the direct extraction of their values.The S-parameter simulation based on the equivalent circuit of 45 nm MOSFET is carried out by ADS circuit simulation software in the frequency range of 1-50 GHz,furthermore,four noise parameters are conducted.Excellent agreement between simulated and measured data shows that the accuracy and practicability of the proposed model and the method of parameter extraction.The accurate extraction technique is explicitly included in the equivalent circuit model to offer higher precision from weak inversion to strong inversion regime.