Markku Leskelä and Mikko Ritala
Who are you?
Mikko Ritala
Markku Leskelä
Markku Leskelä: I am a Professor of Inorganic Chemistry at the University of Helsinki (1990–). My research activities include chemical fabrication of films and nanostructured materials with emphasis on atomic layer deposition (ALD), and catalysis focused on activation of small molecules by metal complexes. I have co-authored more than 600 publications.
Mikko Ritala: I am a Professor of Inorganic Materials Chemistry at the University of Helsinki (2003–). My main research activity is in ALD of thin films for microelectronics and other applications. Another research area is the preparation of nanostructured materials by, for example, templating with ALD and electrodeposition, and electrospinning of nanofibres. I have published over 380 papers.
What prompted you into this field of research?
Markku Leskelä: I started ALD (at that time called ALE) related studies in 1980 after finishing my PhD on luminescent materials. The ALD studies were focused on films needed in electroluminescent displays which were the only commercial application of ALD in the 1980s. In 1990 we started ALD research with Mikko Ritala at the University of Helsinki, with a broad focus on the basic process development. This included precursor synthesis and reaction mechanism studies and looking at possibilities of ALD in various fields. During the 1990s it became clear that ALD was needed in microelectronics and also that our research was focused for high dielectric constant oxides, metal and barrier films. From the very beginning of the emergence of nanotechnology in its various forms it was obvious to us that ALD has a lot to contribute there too, and this has been realized by us and many others.
Can you briefly describe what your paper reports and the impact that it has had on the field?
We described the basic properties of ALD in the paper and showed how very thin films had been deposited on different substrates. We also discussed the nanolaminate concept we had introduced a few years earlier. In the outlook we speculated the suitability of ALD to nanotechnology. In the 1990s nanotechnology was quite a new area and no one had discussed the connection between ALD and nanotechnology. In that sense the paper was visionary.
Can you detail what direction your research went following on from this article and, if applicable, how the results reported in this article helped to influence this?
ALD enables the deposition of thin conformal films in a controlled way on substrates of any size and shape. Now it is clear that ALD is a very suitable tool for growing films on nanomaterials and tuning their properties. The literature contains 1200+ papers, 80+ reviews and 2 books on ALD in nanotechnology. Our review can be considered as a trigger for this field.