Research On Temperature Characteristics And Modeling Of FinFET

With the continuous reduction of transistor feature size,the transistor short-channel effect is becoming more and more significant.Meantime,the performance of traditional planar structure MOSFET is difficult to meet the requirements of production.However,three-dimensional gate structure FinFET devices with high integration and low power consumption can effectively suppress the short-channel effect.As a bridge connecting circuit design and process production,modeling is the simulation basis of circuit designing on the one hand,which reduces design time costs.On the other hand,modeling guides process improvement,improves product yield and reduces production costs.In the context of the rapid development of the field of low-temperature semiconductors,lowtemperature integrated circuits play a huge role in aerospace technology,medical equipment and other fields related to national development.However,the industry does not have a set of variable temperature commercial models suitable for room temperature to extremely low temperature conditions at present.So it is indispensable to study the characteristics of extremely low temperature devices and establish extremely low temperature FinFET models.Therefore,this thesis carries out a series of studies on the temperature characteristics of 14 nm bulk silicon FinFET.Firstly,starting from the structure and working principle of FinFET devices,this thesis introduces the important high-order effects and low-temperature effects that need to be considered in device modeling,summarizes the influence of device structure characteristics on electrical parameters,and discusses the influence of channel length modulation effect,short channel effect,frequency distribution effect,temperature effect,on device performance and so on.The on-chip test system is also elaborated in detail,and the test structure,test instrument,test environment and test methods used in this thesis are introduced.Then,this thesis compares and analyzes the advantages and disadvantages of some common deembedding methods in academia and industry,and introduces the Open-Short deembedding method that combines testing and computing in this thesis.A 0.2GHz-66.2GHz RF small-signal equivalent circuit model suitable for bulk silicon FinFET devices from room temperature to 84 K is established,and the extraction process of each model parameter in the small-signal model is derived in detail.Then the accuracy of the model is verified by comparing the simulation results and the test data under the Sparameters of five transistors at five temperatures.The root mean square error of the small-signal equivalent circuit model does not exceed 0.038.Finally,starting from the flicker noise model,this thesis analyzes the internal temperature characteristics of the channel under working conditions thdddrough the noise characteristics of the device,and proposes a temperature-dependent threshold voltage extraction method,which corrects the traditional threshold voltage formula.On the basis of the modified threshold voltage model,starting from the Poisson equation,a low-doped silicon FinFET variable temperature DC model suitable for 84K-295 K based on surface potential analysis is established,and the reliability of the model is verified by comparing the DC model simulation results with the test data of five sets of NFinFETs,and the relative root mean square error of the variable temperature DC model does not exceed9.7%.In addition,a drain-source current model based on the core of the commercial PSP model is studied and established.and the carrier-related parameters in the model are temperature corrected,and the relative rms error of the drain-source current model does not exceed 10.2%,which greatly improves the applicability and accuracy of the wide temperature range of the commercial model.