skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Epitaxial two dimensional aluminum films on silicon (111) by ultra-fast thermal deposition

Abstract

Aluminum thin films are known for their extremely rough surface, which is detrimental for applications such as molecular electronics and photonics, where protrusions cause electrical shorts or strong scattering. We achieved atomically flat Al films using a highly non-equilibrium approach. Ultra-fast thermal deposition (UFTD), at rates >10 nm/s, yields RMS roughness of 0.4 to 0.8 nm for 30-50 nm thick Al films on variety of substrates. For UFTD on Si(111) substrates, the top surface follows closely the substrate topography (etch pits), indicating a 2D, layer-by-layer growth. The Al film is a mixture of (100) and (111) grains, where the latter are commensurate with the in-plane orientation of the underlying Si (epitaxy). We show the use of these ultra-smooth Al films for highly reproducible charge-transport measurements across a monolayer of alkyl phosphonic acid as well as for plasmonics applications by directly patterning them by focused ion beam to form a long-range ordered array of holes. UFTD is a one-step process, with no need for annealing, peeling, or primer layers. It is conceptually opposite to high quality deposition methods, such as MBE or ALD, which are slow and near-equilibrium processes. For Al, though, we find that limited diffusion length (and good wetting)more » is critical for achieving ultra-smooth thin films.« less

Authors:
; ;  [1]; ;  [2];  [3]
  1. Department of Materials and Interfaces, Weizmann Institute of Science, POB 26, Rehovot 76100 (Israel)
  2. Department of Chemical Research Support, Weizmann Institute of Science, POB 26, Rehovot 76100 (Israel)
  3. Department of Chemical Physics, Weizmann Institute of Science, POB 26, Rehovot 76100 (Israel)
Publication Date:
OSTI Identifier:
22089253
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 111; Journal Issue: 12; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM; ANNEALING; DEPOSITION; DIFFUSION; DIFFUSION LENGTH; EQUILIBRIUM; ION BEAMS; LAYERS; PYROLYSIS; ROUGHNESS; SCATTERING; SILICON; SPECTROSCOPY; SURFACES; THIN FILMS; VAPOR PHASE EPITAXY

Citation Formats

Levine, Igal, Li Wenjie, Vilan, Ayelet, Yoffe, Alexander, Feldman, Yishay, and Salomon, Adi. Epitaxial two dimensional aluminum films on silicon (111) by ultra-fast thermal deposition. United States: N. p., 2012. Web. doi:10.1063/1.4730411.
Levine, Igal, Li Wenjie, Vilan, Ayelet, Yoffe, Alexander, Feldman, Yishay, & Salomon, Adi. Epitaxial two dimensional aluminum films on silicon (111) by ultra-fast thermal deposition. United States. doi:10.1063/1.4730411.
Levine, Igal, Li Wenjie, Vilan, Ayelet, Yoffe, Alexander, Feldman, Yishay, and Salomon, Adi. Fri . "Epitaxial two dimensional aluminum films on silicon (111) by ultra-fast thermal deposition". United States. doi:10.1063/1.4730411.
@article{osti_22089253,
title = {Epitaxial two dimensional aluminum films on silicon (111) by ultra-fast thermal deposition},
author = {Levine, Igal and Li Wenjie and Vilan, Ayelet and Yoffe, Alexander and Feldman, Yishay and Salomon, Adi},
abstractNote = {Aluminum thin films are known for their extremely rough surface, which is detrimental for applications such as molecular electronics and photonics, where protrusions cause electrical shorts or strong scattering. We achieved atomically flat Al films using a highly non-equilibrium approach. Ultra-fast thermal deposition (UFTD), at rates >10 nm/s, yields RMS roughness of 0.4 to 0.8 nm for 30-50 nm thick Al films on variety of substrates. For UFTD on Si(111) substrates, the top surface follows closely the substrate topography (etch pits), indicating a 2D, layer-by-layer growth. The Al film is a mixture of (100) and (111) grains, where the latter are commensurate with the in-plane orientation of the underlying Si (epitaxy). We show the use of these ultra-smooth Al films for highly reproducible charge-transport measurements across a monolayer of alkyl phosphonic acid as well as for plasmonics applications by directly patterning them by focused ion beam to form a long-range ordered array of holes. UFTD is a one-step process, with no need for annealing, peeling, or primer layers. It is conceptually opposite to high quality deposition methods, such as MBE or ALD, which are slow and near-equilibrium processes. For Al, though, we find that limited diffusion length (and good wetting) is critical for achieving ultra-smooth thin films.},
doi = {10.1063/1.4730411},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 12,
volume = 111,
place = {United States},
year = {2012},
month = {6}
}