Public defence in Micro- and nanosciences, M.Sc.(Tech.) Heli Seppänen
- Public defence from the Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering
When
Where
Event language(s)
The title of the thesis: Plasma-enhanced atomic layer deposition of aluminum nitride: characteristics and applications
Doctoral student: Heli Seppänen
Opponent: Prof. Henrik Pedersen, Linköping University, Sweden
Custos: Prof. Harri Lipsanen, Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering
Atomic Layer Deposition (ALD) is a Finnish invention that can be used to grow conformal thin films atomic layer by atomic layer even on complex 3D surface structures. The shrinking of electronic components has made ALD an attractive and competitive alternative for growing thin films, and it has been a rapidly developing field of nanotechnology since the beginning of the 2000s.
The challenges of the technology are the slow growth rate and the quality of the films, which is why ALD films have not been suitable for many applications. The aim of the thesis was to develop new and improve current processes and applications for thin films grown with plasma-enhanced ALD (PEALD) for research and industry. The work focused on improving the crystal quality of aluminum nitride (AlN) thin films by a cyclic plasma treatment, atomic layer annealing, which enables the use of PEALD in new applications that other faster deposition techniques cannot cover due to, for example, the shape of the surface.
Atomic layer annealing in the PEALD process was demonstrated to enable improved film quality and purity. The growth of thin film on vertical sidewalls was also demonstrated. In addition, a piezoelectric aluminum nitride thin film was achieved, which is useful for various sensor applications. Overall, the results are a promising start for the future of utilizing atomic layer annealing in PEALD processes.
Keywords: plasma-enhanced atomic layer deposition, PEALD, thin films, atomic layer annealing
Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/
Doctoral theses in the School of Electrical Engineering: https://aaltodoc.aalto.fi/handle/123456789/53
Zoom Quick Guide: https://www.aalto.fi/en/services/zoom-quick-guide