The Effects of Oxidants on the Growth Behavior of PbTiO3 Thin Film by Atomic Layer Deposition

Abstract

PbTiO 3 thin films were deposited on Si and Ru substrates by atomic layer deposition (ALD) at a substrate temperature of 200 o C using H 2 O and O 3 as oxidants. When H 2 O was used as the oxidant for both Pb-and Ti-precursors, film growth was most effective under the PbO vs. TiO 2 growth cycle ratio where stoichiometry (Pb/Ti concentration ratio = 1) of the film could be achieved. The previously reported catalytic effect observed in the PbTiO 3 ALD process was attributed to the enhanced growth of the component oxide layer, i.e. PbO and TiO 2 , by previously formed stoichiometric PbTiO 3 phase. On the other hand, when H 2 O and O 3 were used for Pb-and Ti-precursors, respectively, the growth rate increased with increasing PbO vs. TiO 2 growth cycle ratio. This was attributed to the effects of O 3 used for the Ti-precursor on the adsorption of Pb-precursor during the subsequent PbO growth step.

Unusual Growth Behavior of Atomic Layer Deposited PbTiO3 Thin Films Using Water and Ozone As Oxygen Sources and Their Combination

“…First of all, the effect of the oxygen source used to deposit a layer of titania for the subsequent growth of a layer of PbO x was considered. This study was already published elsewhere . It shows that (i) a PbO x layer enhances the growth of the TiO 2 layer, and vice versa (this has been attributed to a catalytic effect, such as those already observed in a multioxide ALD component ,, ), (ii) the growth of PbO x on TiO 2 is enhanced when H 2 O was used as an oxygen source for the Ti precursor compared with O 3 , and (iii) the Pb/Ti ratio increases more quickly when O 3 is used to grow the TiO 2 layer.…”

“…The samples were loaded into the ALD chamber again for subsequent PbO x growth. Furthermore, prior to the ALD of PbO x using O 3 , rather thick ( n cy = 400) PbO x films were deposited on the substrates using H 2 O to protect the substrates from being damaged . Figure a,b shows the changes in the Pb LD of the PbO x films grown on Si and Ru substrates using H 2 O and O 3 as oxygen sources, respectively, as a function of n cy .…”