Accueil arrow News arrow Annoucement for a Postdoctoral Position in IEMN
Annoucement for a Postdoctoral Position in IEMN
Post-doctoral position in
Institut d’Electronique, Microélectronique et Nanotechnologies (IEMN), UMR CNRS 8520, Université des Sciences et Technologies de Lille  ( )
Equipe de Physique des Ondes, Nanostructures et Interfaces (EPHONI)
The postdoctoral position is proposed in the frame of the FP7-ICT integrating project “Nano Packaging technology for Interconnect and Heat Dissipation (Nanopack)”, involving 14 partners from 8 European countries (see the website )

Title: Numerical modelling of phonon transport and thermal conductivity of nanoparticles on SOI substrates

Context of the project:
Thermal management of chip based electronic devices is becoming one of the largest bottlenecks to increased performance and integration density. Modern silicon microelectronics is now firmly in the nanoscale regime with many experiments demonstrating significantly reduced thermal transport due to the close proximity of interfaces and phonon confinement in sub 50nm SOI type structures. The consequence of phonon quantisation in the thin silicon channel is reduced group velocity and, consequently, reduced thermal conduction inside the silicon film. Moreover, the proposed novel designs in this area while showing improvements in electrical performance create additional thermal dissipation and/or thermal resistance due to size restrictions in the thermal contact area that also lead to phonon scattering related resistance increases. The overall objective of the NANOPACK project is to develop new thermal interface technologies for low thermal resistance by employing nano-modified surfaces and materials along with methods to characterize and simulate them with respect to thermal, electrical and reliability-related properties. On the theoretical side, the general aim of the project is to use simulative and nano-analytical methods to understand heat transport on a nano/micro scale.

Objectives of the research project:

Two types of generic structures have been proposed to be investigated, namely lamellar structures of SOI type materials and nanoparticles on SOI substrates. Our objectives are to develop simulation techniques to calculate the vibrational spectra of these structures and mostly evaluate the effect of phonon dispersion, as well as geometrical and material parameters, on their thermal conductivities. For this purpose, the candidate will be familiarized with some simulation techniques such as finite difference time domain, finite element and plane wave expansion methods already developed in the frame of elasticity theory by the group in Lille. These methods enable us to calculate the band structure and phonon transport in inhomogeneous materials and, in particular, in phononic crystals constituted by a periodic repetition of inclusions in a background material. The development of atomic force field models for small nanostructures would be also welcome. The main purpose of the project is to use these results to obtain the thermal conductivity in the above structures. A first approximation, assuming the coherence of the phonons in the whole structure, would consist of using the Landauer’s approach to calculate the phonon transmission and thermal conductance. In contrast, a Boltzmann transport equation approach should be developed to emphasize the effect of diffuse scattering at the contacts between the nanoparticles and/or thin films. Transport of heat can be tested versus different assumptions about the phonon mean free path and relaxation time. The ultimate objective is the optimum proposition of geometries and materials for the best thermal performance.
Finally, depending on the available time, the simulation methods developed during the project can also be used to investigate light scattering by phonons in SOI structures, in collaboration with the Raman experiments performed by other partners.     
Duration: One or possibly two years.

The Candidate should hold a PhD in solid state physics or material science, or in mechanical or electrical engineering. A good background in physics and simulation techniques and an experience with transport phenomena (in particular on the basis of Boltzmann equation techniques) are required.

Contact: Interested candidates should send their resume, publication list and contact information to:
Yan Pennec ( ) or
Bahram Djafari Rouhani ( ).
Application will be accepted until position is filled

Lost Password?
Project co-funded by the European Commission under the "Information and Communication Technologies" Seventh Framework Programme (2007-2013)
Contact: Dr. Afshin Ziaei, NANOPACK Coordinator,