scholarly journals Impurity effects on the adhesion of aluminum films on sapphire substrates

1998 ◽  
Author(s):  
J.A. Schneider ◽  
S.E. Guthrie ◽  
W.M. Clift ◽  
N.R. Moody ◽  
M.D. Kriese
Keyword(s):  
Impurity Effects ◽  
Aluminum Films ◽  
Sapphire Substrates

scholarly journals Impurity effects on the adhesion of aluminum films on sapphire substrates

1999 ◽  
Vol 259 (2) ◽  
pp. 253-260 ◽  
Author(s):  
J.A. Schneider ◽  
S.E. Guthrie ◽  
M.D. Kriese ◽  
W.M. Clift ◽  
N.R. Moody
Keyword(s):  
Impurity Effects ◽  
Aluminum Films ◽  
Sapphire Substrates

Properties and Fracture Resistance of Thin Polycrystalline Aluminum Films on Sapphire Substrates

1995 ◽  
Vol 403 ◽  
Author(s):  
N. R. Moody ◽  
D. Medlin ◽  
S. Guthrie ◽  
R. Q. Hwang ◽  
K. F. McCarty
Keyword(s):  
Polycrystalline Aluminum ◽  
Plastic Properties ◽  
Aluminum Films ◽  
Sapphire Substrates ◽  
Nominal Thickness ◽  
High Resolution Tem ◽  
Interface Hardness ◽  
Thin Polycrystalline ◽  
Film Substrate ◽  
Single Crystal Sapphire

AbstractWe employed nanoindentation, continuous microscratch testing, and high resolution TEM to determine the effect of structure on the properties and resistance to fracture of thin polycrystalline aluminum films deposited onto single crystal sapphire substrates at 25°C and 250°C. These films had a nominal thickness of 90 nm and a grain size of 160 nm. The elastic and plastic properties were similar for both films. The elastic moduli superimposed, increasing from bulk aluminum values at the surface to sapphire values at the interface. Hardness values also superimposed, but were constant through the film thickness at a value between aluminum and sapphire. In contrast, susceptibility to fracture varied markedly between the films with the 25°C film exhibiting abrupt failure along the film-substrate interface while the 250'C film gave no indication of fracture in the film, along the interface, or in the substrate under the conditions tested.

Epitaxial growth and characterization of high-quality aluminum films on sapphire substrates by molecular beam epitaxy

CrystEngComm ◽  
2014 ◽  
Vol 16 (33) ◽  
pp. 7626-7632 ◽  
Author(s):  
Wenliang Wang ◽  
Weijia Yang ◽  
Zuolian Liu ◽  
Yunhao Lin ◽  
Shizhong Zhou ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Epitaxial Films ◽  
High Quality ◽  
Aluminum Films ◽  
Sapphire Substrates

2 inch high-quality Al epitaxial films with sharp and abrupt Al/Al2O3 interfaces have been grown on sapphire substrates by molecular beam epitaxy with an in-plane alignment of Al[11̄0]/Al2O3[11̄00].

scholarly journals Interface Effects on the Adhesion of Thin Aluminum Films

1997 ◽  
Vol 472 ◽  
Author(s):  
J.A. Schneider ◽  
S. Guthrie ◽  
N.R. Moody
Keyword(s):  
Thin Films ◽  
Fracture Toughness ◽  
Vapor Deposition ◽  
Scratch Testing ◽  
Aluminum Films ◽  
Sapphire Substrates ◽  
Thin Aluminum ◽  
Scratch Tests ◽  
Interface Effects

ABSTRACTDifferences in the adhesion and fracture toughness of aluminum films on sapphire due to the presence of controlled contaminants are being investigated. Adhesion is evaluated by use of nanoindentation and continuous scratch tests. A comparison was made of the properties of textured thin films of aluminum (178 to 1890 nm) that were vapor deposited onto (0001) oriented sapphire substrates. A very thin (1 nm) layer of carbon was deposited at the interface of selected samples prior to the vapor deposition of the aluminum. Spalling was observed during continuous scratch testing in specimens with carbon at the interface but not in specimens without carbon at the interface.

A method for making substrate-independent hardness measurements of soft metallic films on hard substrates by nanoindentation

2003 ◽  
Vol 18 (6) ◽  
pp. 1383-1391 ◽  
Author(s):  
Ting Y. Tsui ◽  
C. A. Ross ◽  
G. M. Pharr
Keyword(s):  
Thin Films ◽  
Contact Area ◽  
Empirical Relationship ◽  
New Method ◽  
Metallic Films ◽  
Aluminum Films ◽  
Sapphire Substrates ◽  
Substrate Independent ◽  
Hard Substrates ◽  
Penetration Depths

A new method for making substrate-independent hardness measurements by nanoindentation techniques that applies to soft metallic films on very hard substrates is presented. The primary issue to be addressed is substrate-induced enhancement of indentation pileup and the ways it influences the indentation contact area. On the basis of experimental observations of soft aluminum films deposited on silicon, glass, and sapphire substrates, an empirical relationship was derived that relates the amount of pileup to the contact depth. From this relationship and the associated experimental observations, a method was developed that allows the intrinsic hardness of the film to be estimated, even when the indenter penetrates through the film into the substrate. The method should prove useful for very thin films (<100 nm) in which it is not possible to make measurements at penetration depths small enough to avoid subtrate effects.

Effect of Carbon on the Adhesion of Aluminum Films to Sapphire Substrates

1998 ◽  
Vol 522 ◽  
Author(s):  
J. A. Schneider ◽  
S. E. Guthrie ◽  
M. D. Kriese ◽  
W. M. Clift ◽  
N. R. Moody
Keyword(s):  
Aluminum Films ◽  
Sapphire Substrates

Nucleation mechanism for epitaxial growth of aluminum films on sapphire substrates by molecular beam epitaxy

2016 ◽  
Vol 54 ◽  
pp. 70-76 ◽  
Author(s):  
Yunnong Zhu ◽  
Wenliang Wang ◽  
Weijia Yang ◽  
Haiyan Wang ◽  
Junning Gao ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Nucleation Mechanism ◽  
Aluminum Films ◽  
Sapphire Substrates

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Hetero-Epitaxy of Group Va Metals on Sapphire

1972 ◽  
Vol 30 ◽  
pp. 492-493
Author(s):  
J. E. O'Neal ◽  
J. J. Bellina ◽  
B. B. Rath
Keyword(s):  
Thermal Contact ◽  
High Vacuum ◽  
Electron Beam Evaporation ◽  
Ultra High Vacuum ◽  
Backing Plate ◽  
Sapphire Substrates ◽  
Deposition Parameters ◽  
Polishing Damage ◽  
Reflection Electron Diffraction

Thin films of the bcc metals vanadium, niobium and tantalum were epitaxially grown on (0001) and sapphire substrates. Prior to deposition, the mechanical polishing damage on the substrates was removed by an in-situ etch. The metal films were deposited by electron-beam evaporation in ultra-high vacuum. The substrates were heated by thermal contact with an electron-bombarded backing plate. The deposition parameters are summarized in Table 1.The films were replicated and examined by electron microscopy and their crystallographic orientation and texture were determined by reflection electron diffraction. Verneuil-grown and Czochralskigrown sapphire substrates of both orientations were employed for each evaporation. The orientation of the metal deposit was not affected by either increasing the density of sub-grain boundaries by about a factor of ten or decreasing the deposition rate by a factor of two. The results on growth epitaxy are summarized in Tables 2 and 3.

Synchrony of Digestion of SV40 DNA by Exonuclease III Determined by EM

1975 ◽  
Vol 33 ◽  
pp. 674-675
Author(s):  
Ray Wu ◽  
G. Ruben ◽  
B. Siegel ◽  
P. Spielman ◽  
E. Jay
Keyword(s):  
Dark Field ◽  
Uranyl Acetate ◽  
Enzyme Digestion ◽  
Dna Molecules ◽  
Exonuclease Iii ◽  
Aluminum Films ◽  
Double Stranded Dna ◽  
Before And After ◽  
Exo Iii ◽  
Sv40 Dna

A method for determining long nucleotide sequences of double-stranded DNA is being developed. It involves (a) the synchronous digestion of the DNA from the 3' ends with EL coli exonuclease III (Exo III) followed by (b) resynthesis with labeled nucleotides and DNA polymerase. A crucial factor in the success of this method is the degree to which the enzyme digestion proceeds synchronously under proper conditions of incubation (step a). Dark field EM is used to obtain accurate measurements on the lengths and distribution of the DNA molecules before and after digestion with Exo III, while gel electrophoresis is used in parallel to obtain a mean length for these molecules. It is the measurements on a large enough sample of individual molecules by EM that provides the information on how synchronously the digestion proceeds. For length measurements, the DNA molecules were picked up on 20-30 Å thick carbon-aluminum films, using the aqueous Kleinschmidt technique and stained with 7.5 x 10-5M uranyl acetate in 90% ethanol for 3 minutes.

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