National Center for Design of
Biomimetic Nanoconductors

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Umberto Ravaioli

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Umberto Ravaioli is a Professor in the Department of Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign. He is an expert in the area of theory of semiconductor devices and his research work has focused on large scale simulation of charge transport in solid-state and semiconductor device simulation.  His expertise ranges from numerical solution of partial differential equations for continuum transport models to particle simulation using random Monte Carlo techniques. 

Research

Current work has concentrated on ultra-scaled silicon device simulation and on charge transport in ionic channels.  His work on semiconductor device simulation has produced the particle Monte Carlo simulator MOCA (Duncan et al., 1998; Winstead et al., 2003; Kathawala et al., 2003; Kathawala and Ravaioli, 2003), both for 2-D and 3-D self-consistent simulation, which is now widely used by industrial research groups (Intel, Motorola, AMD, Texas Instruments) and by many collaborators at academic institutions for electron transport in a variety of applications.  The most recent 3-D applications of MOCA are for silicon MOS transistors characterized by narrow conduction channels, for example the FinFET and the Tri-gate MOSFET.  These devices have many analogies with ionic channels from the point of view of simulation, in the fact that charge transport is simulated through a narrow channel between two charge reservoir contacts.  Using this expertise, Ravaioli’s group has developed a transport Monte Carlo simulator for ionic channels, bioMOCA (van der Straaten et al., 2005), which is based on an implicit water model, accounts for ion-water interaction by using a scattering rate directly related to the diffusivity, and has been modified to account for the details of ionic size (van der Straaten et al., 2005). 

In addition, he has developed a robust simulation framework for continuum transport in ionic channels (van der Straaten et al., 2003), using an industrial grade simulation package, PROPHET, which embodies the state-of-the-art in partial differential equations solution for charge transport, a problem which has strict requirements for solution stability and convergence.  Ravaioli is an active participant to the Network for Computational Nanotechnology (NCN) both for its research and educational efforts.  The biological transport applications with bioMOCA and PROPHET are in the process to be made available as community codes and as on-line applications on the national TeraGrid through the nanoHUB portal of NCN . The work of the Ravaioli lab is an essential link at the level of stochastic dynamics between the semiconductor engineering approaches and the computational chemistry approaches to understanding permeation.

Related Publications

Sotomayor, M., van der Straaten, T.A., Ravaioli, U., and Schulten, K. (2006), "Electrostatic Properties of the Mechanosensitive Channel of Small Conductance MscS," Biophysical Journal, 90, 3496-3510.

G.A. Kathawala, B. Winstead and U. Ravaioli, "Monte Carlo simulation of double-gate MOSFETs," IEEE Transactions on Electron Devices, vol. 50, pp. 2467-2473, 2003.

G.A. Kathawala, T. van der Straaten and Umberto Ravaioli, “Application of Grid Focusing Methodology to Transport Monte Carlo Model for Ion Channel Simulation,” 2005 NSTI Nanotechnology Conference, Anaheim, CA, May 8-12, 2005.

G.A. Kathawala and U. Ravaioli, 3-D Monte Carlo simulations of FinFETs, Technical Digest of IEEE International Electron Devices Meeting (IEDM 2003), pp. 683-686, Dec. 8-10, 2003.

M. Sotomayor, T. van der Straaten, U. Ravaioli and K. Schulten, "Multiscale Modeling of Gating and Ion Conduction in the Mechanosensitive Channel of Small Conductance MscS, Biophysical Society Meeting, Long Beach, CA, February 12-16, 2005.

T.A. van der Straaten, G. Kathawala, A. Trellakis, R.S. Eisenberg and U. Ravaioli, "BioMOCA – a Boltzmann transport Monte Carlo model for ion channel simulation," Molecular Simulation, vol. 31, pp. 151-171, 2005.

T.A. van der Straaten, J. Tang, R.S. Eisenberg, U. Ravaioli and N. Aluru, "Simulating ion permeation through the ompF porin ion channel using three-dimensional drift-diffusion theory", Journal of Computational Electronics, vol. 2, pp. 29-47, 2003.

B. Winstead and U. Ravaioli, "A quantum correction based on Schroedinger equation applied to Monte Carlo device simulation", IEEE Transactions on Electron Devices, vol. 50, pp. 440-446, 2003.

C.J. Wordelman and U. Ravaioli, “Integration of a Particle-Particle-Particle-Mesh Algorithm with the Ensemble Monte Carlo Method for the Simulation of Ultra-Small Semiconductor Devices,” IEEE Transaction on Electron Devices, Vol. 47, No. 2, pp. 410-416, 2000.

A Duncan, U. Ravaioli and J. Jakumeit, "Full-Band Monte Carlo Investigation of Hot Carrier Trends in the Scaling of Metal-Oxide-Semiconductor Field-Effect Transistors", IEEE Transactions on Electron Devices, vol. 45 pp. 867-876, 1998.

Related Links

Umberto Ravaioli's Beckman Institute Profile

The National Center for Design of Biomimetic Nanoconductors is funded by Grant Number PHS 2 PN2 EY016570B from the National Institutes of Health through the NIH Roadmap for Medical Research and is based at the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign. Partner institutions include Yale University, University of Southern California, University of Chicago, Illinois Institute of Technology, Sandia National Laboratories, Argonne National Laboratory, Oxford University, Wabash College, University of California, Davis, nanoHUB at Purdue University, and the University of New Mexico.