Title: Effect of the nature of the substrate on the surface chemistry of atomic layer deposition precursors

Abstract

The thermal chemistry of Cu(I)-sec-butyl-2-iminopyrrolidinate, a promising copper amidinate complex for atomic layer deposition (ALD) applications, was explored comparatively on several surfaces by using a combination of surface-sensitive techniques, specifically temperature-programmed desorption and x-ray photoelectron spectroscopy (XPS). The substrates explored include single crystals of transition metals (Ni(110) and Cu(110)), thin oxide films (NiO/Ni(110) and SiO₂/Ta), and oxygen-treated metals (O/Cu(110)). Decomposition of the pyrrolidinate ligand leads to the desorption of several gas-phase products, including CH₃CN, HCN and butene from the metals and CO and CO₂ from the oxygen-containing surfaces. In all cases dehydrogenation of the organic moieties is accompanied by hydrogen removal from the surface, in the form of H₂ on metals and mainly as water from the metal oxides, but the threshold for this chemistry varies wildly, from 270 K on Ni(110) to 430 K on O/Cu(110), 470 K on Cu(110), 500 K on NiO/Ni(110), and 570 K on SiO₂/Ta. Here, copper reduction is also observed in both the Cu 2p_3/2 XPS and the Cu L₃VV Auger (AES) spectra, reaching completion by 300 K on Ni(110) but occurring only between 500 and 600 K on Cu(110). On NiO/Ni(110), both Cu(I) and Cu(0) coexist between 200 and 500 K, and onmore » SiO₂/Ta a change happens between 500 and 600 K but the reduction is limited, with the copper atoms retaining a significant ionic character. Additional experiments to test adsorption at higher temperatures led to the identification of temperature windows for the self-limiting precursor uptake required for ALD between approximately 300 and 450 K on both Ni(110) and NiO/Ni(110); the range on SiO₂ had been previously determined to be wider, reaching an upper limit at about 500 K. Finally, deposition of copper metal films via ALD cycles with O₂ as the co-reactant was successfully accomplished on the Ni(110) substrate.« less

Authors:

Yao, Yunxi ^[1]; Coyle, Jason P. ^[2]; Barry, Seán T. ^[2]; Zaera, Francisco ^[1]

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+ Show Author Affiliations

1. Univ. of California, Riverside, CA (United States). Dept. of Chemistry
2. Carleton Univ., Ottawa, ON (Canada). Dept. of Chemistry

Publication Date:

Tue Nov 01 00:00:00 EDT 2016

Research Org.:

Univ. of California, Riverside, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1474074

Alternate Identifier(s):

OSTI ID: 1330595

Grant/Contract Number:  

FG02-03ER46599; SC0001839

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Chemical Physics

Additional Journal Information:

Journal Volume: 146; Journal Issue: 5; Journal ID: ISSN 0021-9606

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY