Modeling And Simulation Of Evolutionary Multi-Gate MOSFET

As device dimensions continue to shrink, small size effect becomes more and more serious, conventional planar MOSFET structure has reached its physical limits. In order to overcome the short-channel effects, there have been many new device structures, such as double-gate, triple-gate, FinFET, surrounding-gate devices. Intel’s FinFET technology is already in production, multi-gate devices have a better gate control of the channel, which can effectively suppress short-channel effects (SCE) and drain barrier lowering (DIBL). Multi-gate devices are alternatives for the future. As a bridge connecting the circuit design and device fabrication, compact model plays an important role. The modeling and simulation research for new multi-gate MOSFET has important practical significance. This thesis focus on SOI FinFET, junctionless surrounding-gate MOSFET and dual-material dual-gate MOSFET. This thesis established the model of potential, threshold voltage and subthreshold swing, discussed the effects of physical parameters on the performance of the device. The relationship between the DIBL effects and structure parameters is also studied. The problems brought by the miniaturization of devices are analyzed and discussed.Firstly, the dual-gate and tri-gate, SOI and bulk FinFET were compared by simulation. We established the models of potential and threshold voltage for SOI FinFET. By comparing with the results of Sentaurus Sdevice 3-D simulation, we verified the correctness of the models. We analyzed the influence of structural parameters on the device threshold voltage. We also analyzed the short-channel effect and DIBL effect. We established subthreshold current model and the sub-threshold swing model for FinFET. We discussed the relationship between the device subthreshold characteristics and structural parameters. We found sub-threshold characteristics are closely related with silicon fin width Wfin.The second part of this thesis studies junctionless surrounding-gate MOSFET. We established models of potential, threshold voltage, subthreshold swing and DIBL By comparing with the Medici simulation results, we verify the correctness of the model. We discussed impact of cylindrical radius and channel doping of junctionless surrounding-gate MOSFET on the device characteristics. We also discussed the impact of structural parameters on the threshold voltage, subthreshold swing and DIBL.The third part of this thesis studied the dual-material dual-gate MOSFET, and established the models of potential and sub-threshold swing. By comparing the simulation results of Medici, we verified the correctness of the models.This thesis analyzed the physical characteristics and the factors that cause changes in characteristics by establishing models for three different new multi-gate MOSFET. The established analytical models can effectively reflect the physical characteristics. The new multi-gate device is an inevitable trend of future development of the device. The research of modeling and simulation for the new multi-gate MOSFET has great significance.