Thesis based on the Analysis and Simulation of Emerging FET Devices. Implementation in Matlab of analytical models for the characterization of scaling behaviour of FinFET different structures. Physical simulations of such devices in TCAD Synopsis Sentaurus to check the reliability of the implemented models. Study of Tunnel FET as an alternative FET which could overcome FinFET main issues related to scaling. Analytical modelling in Matlab and TCAD Sentaurus simulations in order to investigate TFET behaviour varying structures and materials. Comparative study of nanowire FinFET and TFET, investigating on electrical characteristics, parasitic capacitances, temperature behaviour in TCAD Synopsis Sentaurus.