Structural Studies of Sputtered Ni80Co20/Cu Multilayers

1995 ◽  
Vol 382 ◽  
Author(s):  
X. Bian ◽  
Z. Altounian ◽  
J. O. Ström-Olsen ◽  
M. Sutton ◽  
R. W. Cochrane
Keyword(s):  
Optical Model ◽  
Film Growth ◽  
Growth Direction ◽  
Interface Roughness ◽  
High Angle ◽  
X Ray ◽  
Compositional Modulation ◽  
Large Expansion ◽  
Reflectivity Data ◽  
Coherent Interfaces

ABSTRACTThe structure of magnetron-sputtered Ni80Co20/Cu multilayershas been investigated by low and high-angle X-ray diffractometry. Low-angle x-ray reflectivity data reveal well-defined compositional modulation along the film growth direction for a wide Cii thickness range of 5-40 Å. The data analysis, based on anl optical model, shows that interfacial mixing is limited to ∼3-4 Å As the number of bilayers increased from 8 to 100, the interface roughness increased by a factor of 3. Better layered structures were found for relatively thick Cu layers (tCu>10Å). The high-angle diffraction data were analyzed using a trapezoidal model. The results indicate that the films have a polycrystalline structure with a preferred (111)orientation with coherent interfaces of ∼ 100-240 Ådepending on the Cu layer thickness. The relatively large expansion of (111) spacings in NiCo alloy layers gives rise to the lower atomic ordering in NiCo/Cu multilayers.

Structural and Magnetoresistance Studies of Ni/Co Multilayers

1997 ◽  
Vol 475 ◽  
Author(s):  
J.M. Freitag ◽  
J.M. Ström-Olsen ◽  
Z. Altounian ◽  
R.W. Cochrane
Keyword(s):  
Film Growth ◽  
Classical Model ◽  
Growth Direction ◽  
Interface Roughness ◽  
Thickness Variation ◽  
Zero Field ◽  
Saturation Field ◽  
X Ray ◽  
Superlattice Structure ◽  
Reflectivity Data

ABSTRACTA study of ferromagnetic/ferromagnetic Ni/Co multilayers grown by DC magnetron sputtering with component layer thicknesses between 40 and 5 Å is presented. Structural characterization by small-angle x-ray reflectivity reveals high-quality layered structures with a well-defined composition modulation along the film growth direction. Quantitative interpretation of the superlattice structure parameters, including interface roughness and intermixing, has been performed by modelling the x-ray reflectivity data. Measurements of the magnetotransport properties of these multilayers indicate that the magnetoresistance (MR) effect, Ap ∼ 0.35 μΩ-cm, is roughly constant over the entire compositional range. We attribute the origin of this effect to anisotropie magnetoresistance (AMR). The MR ratio Ap/p, which is as high as 3.0% in a SiO2/(Ni40Å/Co5Å)×6 multilayer with saturation field ∼ 80 Oe, is therefore more strongly dependent on the zero-field resistivity. By fitting a semi-classical model of conduction in multilayers to the resistivity thickness variation, we extracted the mean free paths for conduction in each of the constituent layers as well as the contribution of interfacial scattering in the superlattice structure.

Structural Studies and Magnetotransport Properties of Sputtered Ni/Co Multilayers

1995 ◽  
Vol 384 ◽  
Author(s):  
J.M. Freitag ◽  
X. Bian ◽  
Z. Altounian ◽  
J.O. Ström-Olsen ◽  
R.W. Cochrane
Keyword(s):  
Room Temperature ◽  
Film Growth ◽  
Growth Direction ◽  
Structural Studies ◽  
Dc Magnetron Sputtering ◽  
X Ray ◽  
Compositional Modulation ◽  
Small Fields ◽  
Structural Characterizations ◽  
Magnetoresistive Sensitivity

ABSTRACTFerromagnetic/ferromagnetic Ni/Co multilayers were prepared by DC-magnetron sputtering with component layer thicknesses ranging from 40 Å down to 5 Å. Structural characterizations by x-ray diffractometry show a well-defined compositional modulation along the film growth direction and a preferred (111) crystalline orientation. A longitudinal magnetoresistance ΔR/R over 2.7% with a sensitivity of ~0.11%/Oe was measured at room temperature in small fields less than 20 Oe. The highest room temperature sensitivity obtained in this system was 0.16%/Oe. Magnetoresistive sensitivity was found to vary inversely with the number of bilayers in the multilayers. The magnetic anisotropy of the films as determined by MOKE magnetometry is correlated to the magnetoresistance and indicative of an AMR effect.

Thermal Strain Study of Almost Lattice-Matched Epitaxial InuGa1-uAs1-vP1-v Films on InP(100) Substrates

1989 ◽  
Vol 160 ◽  
Author(s):  
G. Bai ◽  
M-A. Nicolet ◽  
S.-J. Kim ◽  
R.G. Sobers ◽  
J.W. Lee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Epitaxial Film ◽  
Lattice Mismatch ◽  
Thermal Strain ◽  
Growth Direction ◽  
Epitaxial Films ◽  
Double Crystal ◽  
X Ray ◽  
Lattice Matched ◽  
Coherent Interfaces

AbstractSingle layers of ~ 0.5µm thick InuGa1-uAs1-vPv (0.52 < u < 0.63 and 0.03 < v < 0.16) were grown epitaxially on InP(100) substrates by liquid phase epitaxy at ~ 630°C. The compositions of the films were chosen to yield a constant banndgap of ~ 0.8 eV (λ = 1.55 µm) at room temperature. The lattice mismatch at room temperature between the epitaxial film and the substrate varies from - 4 × 10-3 to + 4 × 10-3. The strain in the films was characterized in air by x-ray double crystal diffractometry with a controllable heating stage from 23°C to ~ 700°C. All the samples have an almost coherent interfaces from 23°C to about ~ 330°C with the lattice mismatch accomodated mainly by the tetragonal distortion of the epitaxial films. In this temperature range, the x-ray strain in the growth direction increases linearly with temperature at a rate of (2.0 ± 0.4) × 10-6/°C and the strain state of the films is reversible. Once the samples are heated above ~ 300°C, a significant irreversible deterioration of the epitaxial films sets in.

scholarly journals Fabrication and Evaluation of Large Area Mo/Si Soft X-Ray Multilayer Mirrors at Indus SR Facilities

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
P. N. Rao ◽  
Maheswar Nayak ◽  
G. S. Lodha ◽  
S. K. Rai ◽  
A. K. Srivastava ◽  
...  
Keyword(s):  
Film Growth ◽  
Incident Angle ◽  
Interface Roughness ◽  
Thin Film Growth ◽  
Large Area ◽  
Interface Quality ◽  
Sputtering Deposition ◽  
X Ray ◽  
Transmission Electron ◽  
Film Roughness

Large area Mo/Si multilayer (ML) mirrors with high reflectivity are fabricated using magnetron sputtering deposition system. Thin film growth is optimized for film roughness, density, and interface quality by changing process parameters through fabrication of thin films. Mo/Si MLs are fabricated with varying thickness ratio, number of layer pairs, and periodicity from 0.3 to 0.45, 5 to 65, and 40 to 100 Å, respectively. The samples are characterized using hard X-ray reflectivity and transmission electron microscopy. Soft X-ray performance tests of MLs are done by soft X-ray reflectivity using Indus-1 synchrotron radiation. ML coating with thickness errors of ~0.03% per layer and interface roughness in the range of 2 to 5 Å has been realized. The lateral variation of the periodicity is controlled within 0.5 Å over the  mm2 area of the plane substrate by using substrate motion and appropriate masking arrangement. Maximum variation of periodicity from run to run is less than 0.5 Å. Peak reflectivity of ~63% at wavelength of ~127 Å is achieved for incident angle of 71 degree.

scholarly journals Non-Destructive Characterization of Porous Silicon Using X-Ray Reflectivity

1994 ◽  
Vol 358 ◽  
Author(s):  
E. Chason ◽  
T.R. Guilinger ◽  
M.J. Kelly ◽  
T.J. Headley ◽  
A.J. Howard
Keyword(s):  
Porous Silicon ◽  
Film Growth ◽  
Interface Roughness ◽  
Electrochemical Anodization ◽  
Cross Sectional ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Constant Rate

ABSTRACTUnderstanding the evolution of porous silicon (PS) layers at the early stages of growth is important for determining the mechanism of PS film growth and controlling the film properties. We have used X-ray reflectivity (XRR) to determine the evolution of layer thickness and interfacial roughness during the growth of thin PS layers (< 200 nm) prepared by electrochemical anodization. The porous layer grows at a constant rate for films as thin as 15 nm indicating a very short incubation period during which the surface may be electropolished before the PS structure begins to form. Interface roughness measurements indicate that the top surface of the film remains relatively smooth during growth while the roughness of the PS/silicon interface increases only slightly with film thickness. The XRR results are compared with results obtained from the same films by cross-sectional transmission electron microscopy (XTEM), atomic force microscopy (AFM) and gravimetry.

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

Experimental investigation and modelling of light scattering in a-Si:H solar cells deposited on glass/ZnO:Al substrates

2002 ◽  
Vol 715 ◽  
Author(s):  
J. Krc ◽  
M. Zeman ◽  
O. Kluth ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Solar Cells ◽  
Angular Distribution ◽  
Light Scattering ◽  
Optical Model ◽  
Distribution Functions ◽  
Interface Roughness ◽  
Scattering Parameters ◽  
Good Agreement

AbstractThe descriptive scattering parameters, haze and angular distribution functions of textured ZnO:Al transparent conductive oxides with different surface roughness are measured. An approach to determine the scattering parameters of all internal interfaces in p-i-n a-Si:H solar cells deposited on the glass/ZnO:Al substrates is presented. Using the determined scattering parameters as the input parameters of the optical model, a good agreement between the measured and simulated quantum efficiencies of the p-i-n a-Si:H solar cells with different interface roughness is achieved.

Material Structure of Microcrystalline Silicon Deposited with an Expanding Thermal Plasma

2003 ◽  
Vol 762 ◽  
Author(s):  
C. Smit ◽  
D.L. Williamson ◽  
M.C.M. van de Sanden ◽  
R.A.C.M.M. van Swaaij
Keyword(s):  
Thermal Plasma ◽  
Hydrogen Plasma ◽  
Plasma Chemistry ◽  
Plasma Source ◽  
Growth Direction ◽  
Interaction Time ◽  
Material Structure ◽  
Average Particle ◽  
Microcrystalline Silicon ◽  
X Ray

AbstractExpanding thermal plasma CVD (ETP CVD) has been used to deposit thin microcrystalline silicon films. In this study we varied the position at which the silane is injected in the expanding hydrogen plasma: relatively far from the substrate and close to the plasma source, giving a long interaction time of the plasma with the silane, and close to the substrate, resulting in a short interaction time. The material structure is studied extensively. The crystalline fractions as obtained from Raman spectroscopy as well as from X-ray diffraction (XRD) vary from 0 to 67%. The average particle sizes vary from 6 to 17 nm as estimated from the (111) XRD peak using the Scherrer formula. Small angle X-ray scattering (SAXS) and flotation density measurements indicate void volume fractions of about 4 to 6%. When the samples are tilted the SAXS signal is lower than for the untilted case, indicating elongated objects parallel to the growth direction in the films. We show that the material properties are influenced by the position of silane injection in the reactor, indicating a change in the plasma chemistry.

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