16.9.2022 Hydrogen incorporation in Al2O3 and ZnO thin films grown by atomic layer deposition (Kinnunen)

Atomic layer deposition (ALD) is a novel deposition technique that produces thin and conformal films even on high aspect ratio structures and objects with subnanometer thickness precision. Applications of ALD range from semiconductor industry to packaging and medicine. In this thesis, two metal oxides, Al2O3 and ZnO, were deposited using both temporal and spatial ALD.
FM Sami Kinnunen
Published
16.9.2022

While temporal ALD is more established deposition method, spatial ALD offers higher throughput and a possibility to deposit thin flms on larger substrates. In this study Al2O3 and ZnO were deposited using trimethylaluminium (TMA) and diethylzinc (DEZ), respectively, and using water as an oxygen source. Both Al2O3 and ZnO are common and widely studied ALD materials and the reaction mechanism of these materials are thought to be well understood. However, nonideal conditions such as low deposition temperature or fast deposition can lead to high impurity concentrations. In this thesis precursors containing rare isotopes, namely deuterium (2H) and 18O, were used to study the impurity incorporation with different deposition conditions. It was found out that the impurity hydrogen incorporation depends on the deposition temperature as well as from purging time between the precursor pulses. At low temperatures and when short purges are used, hydrogen in the flm originates mainly from metal precursor. The opposite is true for the high temperatures and long purging times. Similar conclusions apply for both temporal and spatial ALD.

The thesis is published in the JYU Dissertations as a number 558, Jyväskylä 2022, ISBN 978-951-39-9198-2 (PDF), URN:ISBN:978-951-39-9198-2, ISSN 2489-9003. Link to publication:  

M.Sc. Sami Kinnunen defends his doctoral dissertation "Hydrogen incorporation in Al2O3 and ZnO thin films grown by atomic layer deposition" on 16 September 2022 at 12 noon. Opponent Professor Matti Putkonen (University of Helsinki) and Custos Professor Timo Sajavaara (Ä¢¹½Ö±²¥). The doctoral dissertation is held in Finnish.

The audience can also follow the dissertation online: