Research

Atomic Layer Deposition research conducted by HelsinkiALD is a balanced combination of basic and applied topics. It covers basically all areas related to ALD: precursor synthesis and characterization, film growth and characterization, reaction mechanism studies, and the first steps of taking the processes toward applications. A broad range of thin film materials are being studied: oxides, chalcogenides, nitrides, metals, halides, organic and hybrid materials. Area selective deposition is an important topic as well. We collaborate extensively with ASM Microchemistry, which has been located in the Chemicum building since 2004. Together, we form a unique ALD research center with over twenty ALD tools, from small scale to 300 mm wafer reactors.

In addition to ALD, other thin film deposition methods are also available in our laboratory. These methods include electrodeposition, SILAR (successive ionic layer adsorption and reaction), electron beam evaporation (EBE), thermal evaporation and sol-gel.

Nanostructured materials are prepared either directly (fibers by electrospinning and electroblowing, and porous materials by anodisation) or by combining these or other templates with the thin film deposition techniques we work with. Electrospinning is an attractive technique as it allows synthesis of macroscopic amounts of nanofibers in reasonably short times, and with electroblowing the productivity can be increased even further. The fibers possess a high specific surface area much like powders, but they can still be handled like monoliths. While our main focus is on inorganic materials, also organic and composite fibers are being studied. Anodisation, in turn, offers controlled ways to prepare ordered porous layers on silicon, aluminum and several other metals.

ALD LiF film on Si. © Miia MäntymäkiZrO₂ fiber. © Johanna PaajanenMicron-sized particles on Si. © Miia MäntymäkiAnnealed ALD-TiO₂, tilted. © Miika MattinenPorous alumina film on glass formed by anodization. © Marianna KemellNi nanorods. © Marianna KemellALD IrOₓ. © Marianna KemellGLAD Al pillars. © Elina FärmElectrodeposited Cu₂O crystallites. © Georgi PopovALD Ta₂O₅ nanotubes. © Marianna KemellPolycrystalline anatase on Si. © Marianna Kemell