PhD - Leuven | More than two weeks ago
To improve electrostatic control, the channel thickness in ultra-thin body (UTB) transistors is reduced close to the atomic limit. However, when silicon and other bulk materials are scaled to these atomistic dimensions, their electron transport characteristics degrade through increased electron scattering, ultimately limiting device performance and efficiency. Two-dimensional materials, such as graphene, transition metal di-chalcogenides (TMDs), carbon nanotubes, with atomistic size in one or two dimensions, are investigated as alternative channel materials in future field-effect transistors (FETs).
The low-dimensional nature of these materials results in strong coupling to their surroundings and renders them susceptible to imperfections in the environment. In experimental realizations, these non-idealities limit the transport properties, leading to limited device performance compared to state-of-the-art transistors. Correctly accounting for non-idealities is crucial in understanding the fundamental transport properties and strategies to optimize future devices. Since we cannot a-priori determine the limiting effect, a complete description of the transport properties in these low-dimensional materials, encompassing all important effects, is crucial.
In this Ph.D., you will start from an in-house full-band Monte-Carlo solver, developed for 2D materials, which incorporates intrinsic electron-phonon and remote-phonon scattering in 2D materials. You will explore various non-idealities such as surface roughness, interface traps and interactions with the oxide. You will implement the corresponding scattering mechanisms in the 2D Monte Carlo code and study relevant configurations.
This interdisciplinary work requires the Ph.D. candidate to bridge the gap between fundamental materials physics and experiments. Scattering rates will, where feasible, be obtained from atomistic first principles calculations in collaboration with imec’s materials modelling group. You will collaborate closely with experimental groups at imec to identify the important scattering mechanisms and to help explain the limiting mechanisms in experimental devices. With this knowledge, you will compare existing and novel material combinations, optimize the device structure and simulate the device performance.
Required background: Solid-State Physics, Materials Science, Electrical Engineering.
Type of work: 15% literature, 50% modeling and implementation, 35% simulation and interpretation.
Supervisor: Bart Soree
Co-supervisor: Maarten Van de Put
Daily advisor: Gautam Gaddemane
The reference code for this position is 2023-017. Mention this reference code on your application form.