These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
3 files

Mechanistic Study of Nucleation Enhancement in Atomic Layer Deposition by Pre-Treatment with Small Organometallic Molecules

revised on 11.09.2019, 16:20 and posted on 11.09.2019, 16:47 by Camila de Paula, Nathaniel Richey, Li Zeng, Stacey Bent

Thermal atomic layer deposition (ALD) of metals on metal oxide surfaces typically suffers from nucleation delays that result in poor-quality films. The poor nucleation may be caused by a lack of suitable chemisorption sites on the oxide surface which are needed for metal nucleation to occur. In this work, we demonstrate that pre-functionalizing the surface with a sub-monolayer of small organometallic molecules from the vapor phase can lead to a significant increase in surface coverage of the metal deposited by ALD. This process is demonstrated for Pt ALD from (methylcyclopentadienyl)trimethylplatinum (MeCpPtMe3) and O2, with nucleation enhanced almost three-fold at 100 ALD cycles after the pre-treatment, and even more significantly at lower ALD cycle numbers. We hypothesize that the high coverage of the organometallic molecule provides an alternative chemisorption mechanism for the platinum precursor and thus leads to an increase in nucleation sites. The growth of the platinum deposits was investigated in depth though scanning electron microscopy (SEM) and grazing incidence small angle x-ray scattering (GISAXS). These studies show that the pre-treatment results in the growth of larger and more highly ordered Pt nanoparticles at early cycle numbers, which subsequently coalesce into continuous and pinhole free films. Surface pretreatment by organometallic molecules therefore introduces a potential route to achieve improved nucleation and growth of ultrathin films.


New Methods of Activating Atomic Layer Deposition for Materials Synthesis

Basic Energy Sciences

Find out more...


Email Address of Submitting Author


Stanford University



ORCID For Submitting Author


Declaration of Conflict of Interest

The authors declare no competing interests