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Title: XPS study of thermal and electron-induced decomposition of Ni and Co acetylacetonate thin films for metal deposition

Abstract

Optimizing thin metal film deposition techniques from metal-organic precursors such as atomic layer deposition, chemical vapor deposition (CVD), or electron beam-induced deposition (EBID) with the help of surface science analysis tools in ultrahigh vacuum requires a contamination-free precursor delivery technique, especially in the case of the less volatile precursors. For this purpose, the preparation of layers of undecomposed Ni(acac){sub 2} and Co(acac){sub 2} was tried via pulsed spray evaporation of a liquid solution of the precursors in ethanol into a flow of nitrogen on a CVD reactor. Solvent-free layers of intact precursor molecules were obtained when the substrate was held at a temperature of 115 °C. A qualitative comparison of thermally initiated and electron-induced precursor decomposition and metal center reduction was carried out. All deposited films were analyzed with respect to chemical composition quasi in situ by x-ray photoelectron spectroscopy. Thermally initiated decomposition yielded higher metal-to-metal oxide ratios in the deposit than the electron-induced process for which ratios of 60:40 and 20:80 were achieved for Ni and Co, resp. Compared to continuous EBID processes, all deposits showed low levels of carbon impurities of ∼10 at. %. Therefore, postdeposition irradiation of metal acetylacetonate layers by a focused electron beam and subsequent removalmore » of intact precursor by dissolution in ethanol or by heating is proposed as electron beam lithography technique on the laboratory scale for the production of the metal nanostructures.« less

Authors:
; ; ; ;  [1]
  1. Institut für Angewandte und Physikalische Chemie, Universität Bremen, Postfach 330440, D-28334 Bremen (Germany)
Publication Date:
OSTI Identifier:
22592881
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 34; Journal Issue: 4; Other Information: (c) 2016 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 42 ENGINEERING; CARBON; CHEMICAL COMPOSITION; CHEMICAL VAPOR DEPOSITION; COMPARATIVE EVALUATIONS; DECOMPOSITION; DEPOSITS; ELECTRON BEAMS; ELECTRONS; ETHANOL; EVAPORATION; LAYERS; LIQUIDS; METALS; NITROGEN; ORGANOMETALLIC COMPOUNDS; OXIDES; PRECURSOR; THIN FILMS; X-RAY PHOTOELECTRON SPECTROSCOPY

Citation Formats

Weiss, Theodor, Warneke, Jonas, Zielasek, Volkmar, E-mail: zielasek@uni-bremen.de, Swiderek, Petra, and Bäumer, Marcus. XPS study of thermal and electron-induced decomposition of Ni and Co acetylacetonate thin films for metal deposition. United States: N. p., 2016. Web. doi:10.1116/1.4953469.
Weiss, Theodor, Warneke, Jonas, Zielasek, Volkmar, E-mail: zielasek@uni-bremen.de, Swiderek, Petra, & Bäumer, Marcus. XPS study of thermal and electron-induced decomposition of Ni and Co acetylacetonate thin films for metal deposition. United States. doi:10.1116/1.4953469.
Weiss, Theodor, Warneke, Jonas, Zielasek, Volkmar, E-mail: zielasek@uni-bremen.de, Swiderek, Petra, and Bäumer, Marcus. 2016. "XPS study of thermal and electron-induced decomposition of Ni and Co acetylacetonate thin films for metal deposition". United States. doi:10.1116/1.4953469.
@article{osti_22592881,
title = {XPS study of thermal and electron-induced decomposition of Ni and Co acetylacetonate thin films for metal deposition},
author = {Weiss, Theodor and Warneke, Jonas and Zielasek, Volkmar, E-mail: zielasek@uni-bremen.de and Swiderek, Petra and Bäumer, Marcus},
abstractNote = {Optimizing thin metal film deposition techniques from metal-organic precursors such as atomic layer deposition, chemical vapor deposition (CVD), or electron beam-induced deposition (EBID) with the help of surface science analysis tools in ultrahigh vacuum requires a contamination-free precursor delivery technique, especially in the case of the less volatile precursors. For this purpose, the preparation of layers of undecomposed Ni(acac){sub 2} and Co(acac){sub 2} was tried via pulsed spray evaporation of a liquid solution of the precursors in ethanol into a flow of nitrogen on a CVD reactor. Solvent-free layers of intact precursor molecules were obtained when the substrate was held at a temperature of 115 °C. A qualitative comparison of thermally initiated and electron-induced precursor decomposition and metal center reduction was carried out. All deposited films were analyzed with respect to chemical composition quasi in situ by x-ray photoelectron spectroscopy. Thermally initiated decomposition yielded higher metal-to-metal oxide ratios in the deposit than the electron-induced process for which ratios of 60:40 and 20:80 were achieved for Ni and Co, resp. Compared to continuous EBID processes, all deposits showed low levels of carbon impurities of ∼10 at. %. Therefore, postdeposition irradiation of metal acetylacetonate layers by a focused electron beam and subsequent removal of intact precursor by dissolution in ethanol or by heating is proposed as electron beam lithography technique on the laboratory scale for the production of the metal nanostructures.},
doi = {10.1116/1.4953469},
journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
number = 4,
volume = 34,
place = {United States},
year = 2016,
month = 7
}
  • Highlights: • 7 day aged VO(acac){sub 2} sol shows enhanced adhesivity on the SiO{sub 2} compared with non-aged sol. • The aging process has significantly affected the morphologies of VO{sub 2} films. • From the FT-IR spectra, thermal aging process provides the deformation of precursor. • The metal insulator transition (MIT) efficiency (ΔT{sub at2000} {sub nm}) reached a maximum value of 51% at 7 day aging. • Thermal aging process could shorten the aging time of sol solution. - Abstract: Thermochromic properties of vanadium dioxide (VO{sub 2}) have been studied extensively due to their IR reflection applications in energy smartmore » windows. In this paper, we studied the optical switching property of VO{sub 2} thin film, depending on the thermal aging time of the vanadyl acetylacetonate (VO(acac){sub 2}) precursor. We found the alteration of the IR spectra of the precursor by tuning the aging time as well as heat treatments of the precursor. An aging effect of vanadium precursor directly affects the morphologies, optical switching property and crystallinity of VO{sub 2} films. The optimum condition was achieved at the 7 day aging time with metal insulator transition (MIT) efficiency of 50%.« less
  • Results are presented from studies of the process of preparing ThO/sub 2/ films by thermal decomposition of thorium acetylacetonate vapor on backings of copper, nickel, aluminum, and aluminum alloys. The rate of thorium dioxide deposition depends strongly on temperature, the optimum value of which is in the range 450-500/degree/C. Adhesion of the ThO/sub 2/ films to the backings is satisfactory; at thicknesses equal to or greater than about 1 ..mu.., delamination of these from the base is observed, plus destruction. The yield of thorium dioxide does not exceed about 30%, based on the thorium content in the sample of ..beta..-diketonatemore » taken. Annealing the ThO/sub 2/ films under vacuum leads to the evolution of hydrogen, CO, CO/sub 2/ and water. The carbon content of the films attains about 20% by wt. Hydrogen, methane, ethane, CO, CO/sub 2/, acetone, acetylacetone, water, and a small amount of unsaturated hydrocarbons were found among the gaseous products of pyrolysis of thorium acetylacetonate by the mass-spectrometric method.« less
  • Chromium oxide Cr{sub 2}O{sub 3} thin films were prepared by atmospheric-pressure chemical vapor deposition (CVD) methods. For CVD from chromium hexacarbonyl, the lower limit of the reaction temperature was 150 C, which could be reduced to 60 C by irradiation with UV light. The films exhibited preferred overgrowth with a vertically developed three-dimensional coarse structure. On the other hand, shiny smooth films were prepared by CVD from chromium acetylacetonate at a reaction temperature above 400 C. These films showed a significant solar absorptance coupled with a high infrared reflectance, which is necessary for efficient conversion of solar energy into heat.
  • Lanthanum acetylacetonate La(C{sub 5}H{sub 7}O{sub 2}){sub 3}.xH{sub 2}O has been used in the preparation of the precursor solution for the deposition of polycrystalline La{sub 2}O{sub 3} thin films on Si(1 1 1) single crystalline substrates. The precursor chemistry of the as-prepared coating solution, precursor powder and precursor single crystal have been investigated by Fourier Transformed Infrared Spectroscopy (FTIR), differential thermal analysis coupled with quadrupole mass spectrometry (TG-DTA-QMS) and X-ray diffraction. The FTIR and X-ray diffraction analyses have revealed the complex nature of the coating solution due to the formation of a lanthanum propionate complex. The La{sub 2}O{sub 3} thin filmsmore » deposited by spin coating on Si(1 1 1) substrate exhibit good morphological and structural properties. The films heat treated at 800 {sup o}C crystallize in a hexagonal phase with the lattice parameters a = 3,89 A and c = 6.33 A, while at 900 {sup o}C the films contain both the hexagonal and cubic La{sub 2}O{sub 3} phase.« less
  • The apparent reaction orders for the growth of boron films in plasma-enhanced chemical vapor deposition from B/sub 2/ H/sub 6/ + He were measured as a function of the plasma power, which ranged from 0.4 to 1.6 kW. The conditions were as follows: substrate temperature, 890 /degree/C; pressure, 200 Pa; and total flowrate of gases, 200 sccm. It was found that the reaction order (/ital n/) makes a transition from 1/2 to 1 at 900 W with an increase of the plasma power, and which accompanied a corresponding morphological transition. On the basis of a simple kinetic model, the observedmore » reaction-order transition is related with a transition from thermal- to electron-impact decomposition of diborane occurring at 900 W: the /ital n/ of 1/2 observed at the power range below 900 W is attributed to a pyrolysis-dominant growth mechanism in which the association of two BH/sub 3/ into B/sub 2/ H/sub 6/ cannot be neglected, whereas the /ital n/ of 1 observed at the power range above 900 W is related to a growth mechanism in which the electron-impact dissociation of diborane is dominant.« less