Etablissement de modèles compacts de transistors MOS multi grilles nanométriques en vue de leur application pour la conception de circuits

Abstract

We propose a compact model for undoped short-channel nanoscale cylindrical-gate MOSFETs. The drain-current model is written in terms of the mobile charge density. This latter is calculated through the solutions of the surface potential. We take into account the short-channel effects such as the DIBL, the VT Roll-off, the subthreshold slope degradation, and the channel length modulation. The results relative to the developed model are compared with those deduced from numerical simulations using ATLAS tool of SILVACO-TCAD software. They present a good agreement over a range of operation from weak to strong inversion regime and for different bias voltages. We also present a compact modeling of lightly doped Double Gate MOSFET (DG MOSFET). An application of the developed work involves the implementation of DG MOSFET model into a hardware description language, which is Verilog-AMS. The goal is the study and the evaluation of circuits based on DG MOSFET transistor. We then carried out study on the device performances through the simulation and the transient analysis of circuits based on DG MOSFET device, such as the Colpitts oscillator and the inverter gate using a passive load. For that, we use SMASH circuits simulator. The oscillation frequency obtained in the case of the Colpitts oscillator around the GHz. The results of circuits simulations based on DG MOSFET confirm then, the circuit application considered in the beginning of this thesis.