The continuous miniaturization of electronic devices relies on effective wet processes that are routinely used in lithography, etching and cleaning. In advanced technology nodes, where the critical dimensions of devices scale down to sub 10 nm, partial capillary filling of deep trenches and capillary induced deformation of nanostructures present a big challenge in nanofabrication. Understanding the mechanism on how liquid interact with nanostructures is critical for many key process steps, such as gap fill by flowable CVD, nanoscale wet etching and cleaning of high aspect ratio structures in confined space. The same mechanism can be applied to the design of biomimetic superhydrophobic materials for self-cleaning and anti-fouling applications. This Ph.D. topic aims at providing a fundamental understanding by combining different advanced characterization techniques together with modeling approaches that will provide insights into the mechanisms at both the macroscopic and at the atomistic scales.
In-situ characterization techniques are critical for capturing the dynamic process of capillary interactions with nanostructures. Several advanced techniques have been developed in the past few years1–4. In this project, attenuated total reflectance--Fourier transform infrared (ATR-FTIR) spectroscopy will be used to investigate the impact of different surface chemistry and geometry profile on wetting properties of heterogeneous surfaces2,4. Nanoscale structural bending under the influence of capillary interfaces will be characterized by an environmental TEM3. The impact of reduced dimensions, material stacks, structural profiles and surface functionalization on the mechanical rigidity will be systematically investigated both experimentally and theoretically.
The successful candidate should have a solid background in science and engineering, with strong problem-solving skills and good writing and oral communication skills. Some basic programming skills are a plus.
1. Xu, X. et al. Capturing wetting states in nanopatterned silicon. ACS Nano 8, 885–93 (2014).
2. Vrancken, N. et al. Superhydrophobic breakdown on nanostructured surfaces characterized by in-situ ATR-FTIR. Langmuir 33, 3601–3609 (2017).
3. Aabdin, Z. et al. Transient clustering of reaction intermediates during wet etching of silicon nanostructures. Nano Lett. 17, 2953–2958 (2017).
4. Vrancken, N. et al. In-situ ATR-FTIR for dynamic analysis of superhydrophobic breakdown on nanostructured silicon surfaces. Sci. Rep. 8, 1–12 (2018).
Required background: Engineering science
Type of work: 10 % literature, 60% experiments and 30 % modeling
Supervisor: Stefan De Gendt, ,
Daily advisor: XiuMei Xu
The reference code for this position is 2020-044. Mention this reference code on your application form.