dc.contributor.author | Ozgit Akgun, C. | en_US |
dc.contributor.author | Goldenberg, E. | en_US |
dc.contributor.author | Okyay, Ali Kemal | en_US |
dc.contributor.author | Bıyıklı, Necmi | en_US |
dc.date.accessioned | 2015-07-28T12:04:45Z | |
dc.date.available | 2015-07-28T12:04:45Z | |
dc.date.issued | 2014 | en_US |
dc.identifier.issn | 2050-7526 | |
dc.identifier.uri | http://hdl.handle.net/11693/13148 | |
dc.description.abstract | The authors report on the use of hollow cathode plasma for low-temperature plasma-assisted atomic layer
deposition (PA-ALD) of crystalline AlN, GaN and AlxGa1 xN thin films with low impurity concentrations.
Depositions were carried out at 200 C using trimethylmetal precursors and NH3 or N2/H2 plasma. X-ray
photoelectron spectroscopy showed the presence of 2.5–3 at.% O in AlN and 1.5–1.7 at.% O in GaN
films deposited using NH3 and N2/H2 plasma, respectively. No C impurities were detected within the
films. Secondary ion mass spectroscopy analyses performed on the films deposited using NH3 plasma
revealed the presence of O, C (both <1 at.%), and H impurities. GIXRD patterns indicated polycrystalline
thin films with wurtzite crystal structure. Hollow cathode PA-ALD parameters were optimized for AlN
and GaN thin films using N2/H2 plasma. Trimethylmetal and N2/H2 saturation curves evidenced the selflimiting
growth of AlN and GaN at 200 C. AlN exhibited linear growth with a growth per cycle (GPC) of
1.0 A. For GaN, the GPC decreased with the increasing number of deposition cycles, indicating ˚
substrate-enhanced growth. The GPC calculated from a 900-cycle GaN deposition was 0.22 A. ˚
Ellipsometric spectra of the samples were modeled using the Cauchy dispersion function, from which
the refractive indices of 59.2 nm thick AlN and 20.1 nm thick GaN thin films were determined to be 1.94
and 2.17 at 632 nm, respectively. Spectral transmission measurements of AlN, GaN and AlxGa1 xN thin
films grown on double side polished sapphire substrates revealed near-ideal visible transparency with
minimal absorption. Optical band edge values of the AlxGa1 xN films shifted to lower wavelengths with
the increasing Al content, indicating the tunability of band edge values with the alloy composition. | en_US |
dc.language.iso | English | en_US |
dc.source.title | Journal of Materials Chemistry C | en_US |
dc.relation.isversionof | http://dx.doi.org/10.1039/c3tc32418d | en_US |
dc.title | Hollow cathode plasma-assisted atomic layer deposition of crystalline AlN, GaN and AlxGa1−xN thin films at low temperatures | en_US |
dc.type | Article | en_US |
dc.department | Institute of Materials Science and Nanotechnology (UNAM) | en_US |
dc.department | Nanotechnology Research Center (NANOTAM) | en_US |
dc.department | Department of Electrical and Electronics Engineering | en_US |
dc.citation.spage | 2123 | en_US |
dc.citation.epage | 2136 | en_US |
dc.citation.volumeNumber | 2 | en_US |
dc.citation.issueNumber | 12 | en_US |
dc.identifier.doi | 10.1039/c3tc32418d | en_US |
dc.publisher | Royal Society of Chemistry | en_US |
dc.contributor.bilkentauthor | Bıyıklı, Necmi | |
dc.contributor.bilkentauthor | Okyay, Ali Kemal | |