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Title: Epitaxial growth of AlN films via plasma-assisted atomic layer epitaxy

Thin AlN layers were grown at 200–650 °C by plasma assisted atomic layer epitaxy (PA-ALE) simultaneously on Si(111), sapphire (1120), and GaN/sapphire substrates. The AlN growth on Si(111) is self-limited for trimethyaluminum (TMA) pulse of length > 0.04 s, using a 10 s purge. However, the AlN nucleation on GaN/sapphire is non-uniform and has a bimodal island size distribution for TMA pulse of ≤0.03 s. The growth rate (GR) remains almost constant for T{sub g} between 300 and 400 °C indicating ALE mode at those temperatures. The GR is increased by 20% at T{sub g} = 500 °C. Spectroscopic ellipsometry (SE) measurement shows that the ALE AlN layers grown at T{sub g} ≤ 400 °C have no clear band edge related features, however, the theoretically estimated band gap of 6.2 eV was measured for AlN grown at T{sub g} ≥ 500 °C. X-ray diffraction measurements on 37 nm thick AlN films grown at optimized growth conditions (T{sub g} = 500 °C, 10 s purge, 0.06 s TMA pulse) reveal that the ALE AlN on GaN/sapphire is (0002) oriented with rocking curve full width at the half maximum (FWHM) of 670 arc sec. Epitaxial growth of crystalline AlN layers by PA-ALEmore » at low temperatures broadens application of the material in the technologies that require large area conformal growth at low temperatures with thickness control at the atomic scale.« less
Authors:
; ; ; ; ;  [1]
  1. U.S. Naval Research Laboratory, Washington, DC 20375 (United States)
Publication Date:
OSTI Identifier:
22218132
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 8; Other Information: (c) 2013 U.S. Government; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM NITRIDES; CHEMICAL VAPOR DEPOSITION; ELLIPSOMETRY; GALLIUM NITRIDES; LAYERS; LENGTH; MOLECULAR BEAM EPITAXY; NEUTRON DIFFRACTION; NUCLEATION; PLASMA; SAPPHIRE; SEMICONDUCTOR MATERIALS; SUBSTRATES; THICKNESS; X-RAY DIFFRACTION