Surface chemistry of a Cu(I) beta-diketonate precursor and the atomic layer deposition of Cu{sub 2}O on SiO{sub 2} studied by x-ray photoelectron spectroscopy

Journal Article · Tue Jul 01 04:00:00 EDT 2014 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4878815· OSTI ID:22318073

Dhakal, Dileep ^[1]; Waechtler, Thomas; Schulz, Stefan E.; Gessner, Thomas ^[2]; Lang, Heinrich; Mothes, Robert; Tuchscherer, André ^[3]

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1. Center for Microtechnologies – ZfM, Technische Universität Chemnitz, D-09107 Chemnitz (Germany)
2. Center for Microtechnologies – ZfM, Technische Universität Chemnitz, D-09107 Chemnitz, Germany and Fraunhofer Institute for Electronic Nano Systems - ENAS, Technologie-Campus 3, D-09126 Chemnitz (Germany)
3. Institute of Chemistry, Inorganic Chemistry, Technische Universität Chemnitz, D-09107 Chemnitz (Germany)

The surface chemistry of the bis(tri-n-butylphosphane) copper(I) acetylacetonate, [({sup n}Bu{sub 3}P){sub 2}Cu(acac)] and the thermal atomic layer deposition (ALD) of Cu{sub 2}O using this Cu precursor as reactant and wet oxygen as coreactant on SiO{sub 2} substrates are studied by in-situ x-ray photoelectron spectroscopy (XPS). The Cu precursor was evaporated and exposed to the substrates kept at temperatures between 22 °C and 300 °C. The measured phosphorus and carbon concentration on the substrates indicated that most of the [{sup n}Bu{sub 3}P] ligands were released either in the gas phase or during adsorption. No disproportionation was observed for the Cu precursor in the temperature range between 22 °C and 145 °C. However, disproportionation of the Cu precursor was observed at 200 °C, since C/Cu concentration ratio decreased and substantial amounts of metallic Cu were present on the substrate. The amount of metallic Cu increased, when the substrate was kept at 300 °C, indicating stronger disproportionation of the Cu precursor. Hence, the upper limit for the ALD of Cu{sub 2}O from this precursor lies in the temperature range between 145 °C and 200 °C, as the precursor must not alter its chemical and physical state after chemisorption on the substrate. Five hundred ALD cycles with the probed Cu precursor and wet O{sub 2} as coreactant were carried out on SiO{sub 2} at 145 °C. After ALD, in-situ XPS analysis confirmed the presence of Cu{sub 2}O on the substrate. Ex-situ spectroscopic ellipsometry indicated an average film thickness of 2.5 nm of Cu{sub 2}O deposited with a growth per cycle of 0.05 Å/cycle. Scanning electron microscopy and atomic force microscopy (AFM) investigations depicted a homogeneous, fine, and granular morphology of the Cu{sub 2}O ALD film on SiO{sub 2}. AFM investigations suggest that the deposited Cu{sub 2}O film is continuous on the SiO{sub 2} substrate.

• OSTI ID: 22318073
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films Journal Issue: 4 Vol. 32; ISSN 0734-2101; ISSN JVTAD6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMIC FORCE MICROSCOPY
CONCENTRATION RATIO
COPPER OXIDES
ELLIPSOMETRY
OXIDATION
REDUCTION
SCANNING ELECTRON MICROSCOPY
SILICON OXIDES
SUBSTRATES
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
X-RAY PHOTOELECTRON SPECTROSCOPY