Research On Characterization And Model Of Bulk FinFET Devices At Cryogenic Temperature

In half past century,MOS devices have rapidly developed.In order to meet the better performance and lower cost,smaller and smaller size of the MOS devices is needed.However,with the shrinking planar of MOSFETs size the problem within the MOSFET become more and more serious,so the three-dimensional(3D)Fin FET is catching people's eyes now.Due to enhancing the gate-to-channel control capability by the stereo tri-gate structure,Fin FET quickly became the preferred structure in the industry at 22 nm node.Fin FET has a large market space at present,but it has not been well studied in the cryogenic temperature environment with high demand at this stage.There has no Fin FET model suitable for extremely low temperature on the market yet as far as I know.At cryogenic temperatures,the performance of the device changes greatly,which means that there has many serious problems for circuit design.Therefore,it is necessary to study the characteristics of Fin FET devices and establish a Fin FET model at cryogenic temperatures.In this paper,the methods of studying the characteristics of Fin FET devices at crygogenic temperature are presented.Extracted the DC and RF parameters of Fin FET devices,improved the original model based on the BSIM-CMG model.Finally,verified the established cryogenic BSIM-CMG model.The specific research contents of this paper are as follows:(1)Introduced the structure of the Fin FET and made the analogy from the working principle of planar MOSFET to three-dimensional Fin FET devices,the other multi-gate structure devices are also introduced.(2)Introduced the BSIM-CMG model for Fin FET modeling,and derived the core equation of the BSIM-CMG model.(3)Studied the parameters of MOSFET devices at cryogenic temperatures,showed the new effects that will occur at very low temperatures,and analyzed the principle and derivation of the equations for the effects of temperature on carrier mobility and threshold voltage.(4)Measured the DC and RF parameters of the Fin FET device at 77 K,120K,200 K,250K,and 300 K.Extracted the DC and RF parameters from the measured data and analyzed data.Some important parameters such as,mobility,threshold voltage,subthreshold slope,transconductance,parasitic capacitance,maximum cutoff frequency,and oscillation frequency are also shown in this paper,observing the change of this parameters with temperature.(5)Established an equation of the extracted parameters on the change of temperature.Improved the BSIM-CMG model,and applying the model to the temperature range from normal temperature to cryogenic temperature.