Surface chemical mechanisms in room-temperature atomic layer deposition of oxides for controlled pharma release

Purpose and goal

Atomic layer deposition (ALD) is used to make thin layers of different materials atom by atom. ALD is used, among other things, to build up all the chips for all computers and smart mobile phones. Nanexa is a pioneer in using ALD to encapsulate drug particles with a protective shell that allows the drug to be released over a long period of time in the body. The purpose of the project is to understand Nanexa´s ALD processes at the atomic level so that Nanexa can develop new and better processes.

Expected effects and result

Although much is known about the surface chemistry of ALD, almost all previous studies have been performed at high temperatures, 100-200 C. Since drug particles are temperature sensitive, the project will study the surface chemical reactions in ALD at very low temperatures, close to room temperature. The surface chemical models developed within the project will be used by Nanexa to develop new ALD processes, and ultimately new products, based on a much better understanding of today´s processes.

Planned approach and implementation

The project group has already applied for beam time at the SPECIES beamline at MAX IV to study how chemical bonds are broken and formed on surfaces upon exposure to ALD precursors. The technique is called X-ray photoelectron spectroscopy and thanks to the high-intensity X-rays at MAX IV, the measurements can be made at the same pressure as in ALD processes, which gives a much more accurate picture of the surface chemistry than in regular labs where much lower pressure is required.