14 Feb 2006 | Tools | Contributor(s): Anisur Rahman, Jing Wang, Jing Guo, Md. Sayed Hasan, Yang Liu, Akira Matsudaira, Shaikh S. Ahmed, Supriyo Datta, Mark Lundstrom
Calculate the ballistic I-V characteristics for conventional MOSFETs, Nanowire MOSFETs and Carbon NanoTube MOSFETs
Exploring New Channel Materials for Nanoscale CMOS
21 May 2006 | Papers | Contributor(s): Anisur Rahman
The improved transport properties of new channel materials, such as Ge and III-V semiconductors, along with new device designs, such as dual gate, tri gate or FinFETs, are expected to enhance the performance of nanoscale CMOS devices.
Novel process techniques, such as ALD, high-k dielectrics, and metal gates are now being used to experimentally explore such devices. New materials in the channel promise reduced series resistance and higher on-currents. The theoretical assessment of such devices is a challenge because bandstructure, arbitrary wafer orientation, quantum effects and electrostatics must all be treated. In the first part of this work, a
general theoretical approach for the quantum mechanical simulation of n-MOSFETs within the Non Equilibrium Green's Function (NEGF) formalism is introduced, and its application is demonstrated by performing a scaling study for the end of the ITRS Ge device. In the second part of this work, a systematic analysis of the bandstructure effects in deeply scaled n- and p- MOSFETs with Si, Ge, GaAs and InAs channel is performed. Here, a 20 orbital sp3d5s*-SO tight-binding model and a top-of-thebarrier quasi-2D ballistic transport model have revealed important trends in deeply scaled new channel material devices.
Theory of Ballistic Nanotransistors
27 Nov 2002 | Papers | Contributor(s): Anisur Rahman, Jing Guo, Supriyo Datta, Mark Lundstrom
Numerical simulations are used to guide the development of a simple analytical theory for ballistic field-effect transistors. When two-dimensional electrostatic effects are small, (and when the insulator capacitance is much less than the semiconductor (quantum) capacitance), the model reduces to Natori's theory of the ballistic MOSFET. The model also treats twodimensional electrostatics and the quantum capacitance limit where the semiconductor quantum capacitance is much less than the insulator capacitance. This new model provides insights into the performance of MOSFETs near the scaling limit, and a unified framework for assessing and comparing a variety of novel transistors.