The co-reactant role during plasma enhanced atomic layer deposition of palladium
Year of publication
2020
Authors
Feng, Ji-Yu; Minjauw, Matthias M.; Ramachandran, Ranjith K.; Van Daele, Michiel; Poelman, Hilde; Sajavaara, Timo; Dendooven, Jolien; Detavernier, Christophe
Abstract
Atomic layer deposition (ALD) of noble metals is an attractive technology potentially applied in nanoelectronics and catalysis. Unlike the combustion-like mechanism shown by other noble metal ALD processes, the main palladium (Pd) ALD process using palladium(II)hexafluoroacetylacetonate [Pd(hfac)2] as precursor is based on true reducing surface chemistry. In this work, a thorough investigation of plasma-enhanced Pd ALD is carried out by employing this precursor with different plasmas (H2*, NH3*, O2*) and plasma sequences (H2* + O2*, O2* + H2*) as co-reactants at varying temperatures, providing insights in the co-reactant and temperature dependence of the Pd growth per cycle (GPC). At all temperatures, films grown with only reducing co-reactants contain a large amount of carbon, while an additional O2* in the co-reactant sequence helps to obtain Pd films with much lower impurity concentrations. Remarkably, in situ XRD and SEM show an abrupt release of the carbon impurities during annealing at moderate temperatures in different atmospheres. In vacuo XPS measurements reveal the remaining species on the as-deposited surface after every exposure. Links are established between the particular surface termination prior to the precursor pulse and the observed differences in GPC, highlighting hydrogen as the key growth facilitator and carbon and oxygen as growth inhibitors. The increase in GPC with temperature for ALD sequences with H2* or NH3* prior to the precursor pulse is explained by an increase in the amount of hydrogen species that reside on the Pd surface which are available for reaction with the Pd(hfac)2 precursor.
Show moreOrganizations and authors
Publication type
Publication format
Article
Parent publication type
Journal
Article type
Original article
Audience
ScientificPeer-reviewed
Peer-ReviewedMINEDU's publication type classification code
A1 Journal article (refereed), original researchPublication channel information
Publisher
Volume
22
Issue
16
Pages
9124-9136
ISSN
Publication forum
Publication forum level
2
Open access
Open access in the publisher’s service
No
Self-archived
No
Other information
Fields of science
Physical sciences; Chemical sciences
Keywords
[object Object],[object Object],[object Object],[object Object]
Publication country
United Kingdom
Internationality of the publisher
International
Language
English
International co-publication
Yes
Co-publication with a company
No
DOI
10.1039/d0cp00786b
The publication is included in the Ministry of Education and Culture’s Publication data collection
Yes