Sputter Deposition of GMR Spin Valves

2000 ◽  
Vol 616 ◽  
Author(s):  
W. Zou ◽  
X.W. Zhou ◽  
J.J. Quan ◽  
Y.G. Yang ◽  
H.N.G. Wadley ◽  
...  
Keyword(s):  
Film Growth ◽  
Growth Conditions ◽  
Input Power ◽  
Sputter Deposition ◽  
Atomic Scale ◽  
Spin Valves ◽  
Monte Carlo Techniques ◽  
Surfaces And Interfaces ◽  
Interfacial Structures ◽  
Series Of Experiments

AbstractRadio frequency (RF) diode sputtering has been used for the growth of giant magnetoresistive (GMR) metal multilayers. Control of the atomic-scale structure of the surfaces and interfaces within these films is critical for GMR applications. A systematic series of experiments have been conducted to evaluate the dependence of the magnetotransport properties upon the growth conditions (i.e. background pressure, input power) for NiFeCo/CoFe/CuAgAu spin valves during RF diode sputter deposition. By using computational fluid dynamics, plasma, molecular dynamics, and various Monte Carlo techniques, a multiscale modeling approach has investigated the atomic assembly events during film growth. Energetic metal atoms and inert gas ion fluxes are shown to have very strong effects upon interfacial structures. The insights gained have led to novel deposition strategy propopositions for interface morphology control.

scholarly journals Sputter Deposition of Semiconductor Superlattices for Thermoelectric Applications

1996 ◽  
Vol 450 ◽  
Author(s):  
Andrew V. Wagner ◽  
Ronald J. Foreman ◽  
Joseph C. Farmer ◽  
Troy W. Barbee
Keyword(s):  
Film Growth ◽  
Lead Telluride ◽  
Deposition Process ◽  
Growth Conditions ◽  
Sputter Deposition ◽  
High Rate ◽  
Dramatic Improvement ◽  
High Deposition Rate ◽  
High Quality ◽  
Quantum Confined

ABSTRACTTheoretical dramatic improvement of the thermoelectric properties of materials by using quantum confinement in novel semiconductor nanostructures has lead to considerable interest in the thermoelectric community. Therefore, we are exploring the critical materials issues for fabrication of quantum confined structures by magnetron sputtering in the lead telluride and bismuth telluride families of materials. We have synthesized modulated structures from thermoelectric materials with bilayer periods of as little as 3.2 nm and shown that they are stable at deposition temperatures high enough to grow quality films. Issues critical to high quality film growth have been investigated such as nucleation and growth conditions and their effect on crystal orientation and growth morphology. These investigations show that nucleating the film at a temperature below the growth temperature of optimum electronic properties produces high quality films. Our work with sputter deposition, which is inherently a high rate deposition process, builds the technological base necessary to develop economical production of these advanced materials. High deposition rate is critical since, even if efficiencies comparable with CFC based refrigeration systems can be achieved, large quantities of quantum confined materials will be necessary for cost-competitive uses.

Growth of Cubic AlN Films on Sapphire(0001) with Atomic Scale Surface Smoothness by Pulsed Laser Deposition

2010 ◽  
Vol 638-642 ◽  
pp. 2921-2926 ◽  
Author(s):  
Tomohiro Yoshitake ◽  
Tsuyoshi Yoshitake ◽  
Kazushi Sumitani ◽  
Ryota Ohtani ◽  
You Nakagawa ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Growth Conditions ◽  
Atomic Scale ◽  
Laser Deposition ◽  
Normal Surface ◽  
Scale Surface

We have previously reported that -AlN crystallites with diameters of 0.5–1 µm were occasionally grown on sapphire(0001) by pulsed laser deposition, which implied that the migration mobility of the species deposited on the substrate surface might be an insufficient for the film growth of -AlN. In the present study, in order to enhance the crystal growth of -AlN, sapphire(0001) substrates with an atomically smoothness (step-sapphire) were employed. The growth conditions of - and -AlN extended to higher nitrogen-pressures, as compared to those using normal surface sapphire(0001) substrates (normal-sapphire). This is due to the enhancement in the mobility of the deposited species on the substrate surface.

Ohm’s Law Survives to the Atomic Scale

Science ◽  
2012 ◽  
Vol 335 (6064) ◽  
pp. 64-67 ◽  
Author(s):  
B. Weber ◽  
S. Mahapatra ◽  
H. Ryu ◽  
S. Lee ◽  
A. Fuhrer ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Quantum Information Processing ◽  
Silicon Crystal ◽  
Tight Binding ◽  
Atomic Scale ◽  
Single Atom ◽  
Active Device ◽  
Average Spacing ◽  
Surfaces And Interfaces ◽  
Atomic Limit

As silicon electronics approaches the atomic scale, interconnects and circuitry become comparable in size to the active device components. Maintaining low electrical resistivity at this scale is challenging because of the presence of confining surfaces and interfaces. We report on the fabrication of wires in silicon—only one atom tall and four atoms wide—with exceptionally low resistivity (~0.3 milliohm-centimeters) and the current-carrying capabilities of copper. By embedding phosphorus atoms within a silicon crystal with an average spacing of less than 1 nanometer, we achieved a diameter-independent resistivity, which demonstrates ohmic scaling to the atomic limit. Atomistic tight-binding calculations confirm the metallicity of these atomic-scale wires, which pave the way for single-atom device architectures for both classical and quantum information processing.

Observation of the CdTe-GaAs Interface by High Resolution Electron Microscopy

1984 ◽  
Vol 37 ◽  
Author(s):  
N. Otsuka ◽  
L. A. Kolodziejski ◽  
R. L. Gunshor ◽  
S. Datta ◽  
R. N. Bicknell ◽  
...  
Keyword(s):  
High Resolution ◽  
Film Growth ◽  
Substrate Surface ◽  
High Resolution Electron Microscopy ◽  
Gaas Substrates ◽  
Resolution Electron ◽  
Interfacial Structures ◽  
Substrate Preheating ◽  
High Resolution Electron Microscope

AbstractCdTe films have been grown on GaAs substrates with two types of interfaces - one with the epitaxial relation (111)CdTe║ (100)GaAs and the other with (100)CdTe║ (100)GaAs,. High resolution electron microscope observation of the two types of interfaces was carried out in order to determine the role of the substrate surface microstructure in determining the epitaxy. The interface of the former type shows a direct contact between the CdTe and GaAs crystals, while the interface of the latter type has a very thin oxide layer (∼10 Å in thickness) between the two crystals. These observations suggest that details of the substrate preheating cycle prior to film growth is the principle factor in determining which epitaxial relation occurs in this system. The relation between interfacial structures and the origin of the two epitaxial relations is discussed.

scholarly journals In-Situ Thin Film Growth of PbTiO3 By Multi Target Sputtering

1994 ◽  
Vol 341 ◽  
Author(s):  
Thomas Maeder ◽  
Paul Muralt
Keyword(s):  
Lead Oxide ◽  
Film Growth ◽  
Sputter Deposition ◽  
Dielectric Constants ◽  
Thin Film Growth ◽  
Film Morphology ◽  
Reactive Sputter Deposition ◽  
Pt Electrodes ◽  
Oxide Flux

AbstractThe in-situ reactive sputter deposition of PbTiO3 on Pt/Ti/SiO2/Si from two metallic targets was investigated. A minimal lead oxide flux of two to three times the titanium oxide flux is needed in order to obtain stoichiometric films with the perovskite structure. For higher fluxes, the Pb/Ti ratio in the film stays at the stoichiometric value 1; the orientation changes from random to <100>; and the film morphology transforms from a rough to a smooth polycrystalline film. The obtained dielectric constants vary between 40 and 150, the losses between 2 and 4 % (10 kHz). The method could be extended to PbZrxTi1-xO3 for x ≤0.7. The orientation is lost when the Pt electrodes are replaced by RuO2 electrodes.

scholarly journals Nanotribological Performance Factors for Aqueous Suspensions of Oxide Nanoparticles and Their Relation to Macroscale Lubricity

Lubricants ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 49 ◽  
Author(s):  
Biplav Acharya ◽  
Tyler N. Pardue ◽  
Liangliang Su ◽  
Alex I. Smirnov ◽  
Donald W. Brenner ◽  
...  
Keyword(s):  
Initial Study ◽  
Atomic Scale ◽  
Frictional Drag ◽  
Friction Coefficients ◽  
Materials Properties ◽  
Performance Factors ◽  
Aqueous Suspensions ◽  
Series Of Experiments ◽  
Motional Resistance ◽  
Solid Liquid

Quartz crystal microbalance (QCM) measurements of nanotribological properties of statistically diverse materials combinations of nanoparticles and substrate electrodes in aqueous suspensions are reported and compared to macroscale measurements of the same materials combinations for a subset of the nanoparticle combinations. Four ceramic nanoparticles, TiO2, SiO2, Al2O3, and maghemite (γ-Fe2O3) and ten substrate materials (Au, Al, Cr, Cu, Mo, Ni, Pt, SiO2, Al2O3, and SS304) were studied. The QCM technique was employed to measure frequency and motional resistance changes upon introduction of nanoparticles into the water surrounding its liquid-facing electrode. This series of experiments expanded prior studies that were often limited to a single nanoparticle - solid liquid combination. The variations in QCM response from one nanoparticle to another are observed to be far greater than the variation from one substrate to another, indicating that the nanoparticles play a larger role than the substrates in determining the frictional drag force levels. The results were categorized according to the direction of the frequency and motional resistance changes and candidate statistical performance factors for the datasets were generated. The performance factors were employed to identify associations between the QCM atomic scale results and the macroscale friction coefficient measurements. Macroscale measurements of friction coefficients for selected systems document that reductions (increases) in motional resistance to shear, as measured by the QCM, are linked to decreases (increases) in macroscale friction coefficients. The performance factors identified in the initial study therefore appear applicable to a broader set of statistically diverse samples. The results facilitate full statistical analyses of the data for identification of candidate materials properties or materials genomes that underlie the performance of nanoparticle systems as lubricants.

FACET: a two Dimensional Simulator of Polycrystalline thin film Growth

2000 ◽  
Vol 653 ◽  
Author(s):  
Jie Zhang ◽  
James B. Adams
Keyword(s):  
Thin Film ◽  
Film Growth ◽  
Crystal Surface ◽  
Thin Film Growth ◽  
Atomic Scale ◽  
Grain Structure ◽  
Textured Surface ◽  
Two Dimensional ◽  
Polycrystalline Thin Film ◽  
Lattice Monte Carlo

AbstractWe present FACET: a two dimensional simulator to model polycrystalline thin film growth, which links atomic scale processes to macroscopic phenomena. The model is based on the concept of describing the crystal surface in terms of preferred facets. Line segments were used to depict the profile of the grain and grain boundaries. Multiple nuclei are semi-randomly distributed along the textured or non-textured surface, and crystallographycally appropriate facets are created in the nucleation simulation. We use a Kinetic Lattice Monte Carlo (KLMC) method to calculate the inter-facet diffusion rates and use a continuum approach to grow the facets, hence the multiple grains. The software is Windows(95/98/2000/NT) based and has an integrated Graphical User Interface, within which a user can input deposition conditions and experimental and simulation data, visualize the nucleation and growth of the grains, and obtain the final grain structure and texture.

scholarly journals Growth of InN By MBE

2000 ◽  
Vol 5 (S1) ◽  
pp. 181-187
Author(s):  
W.-L. Chen ◽  
R. L. Gunshor ◽  
Jung Han ◽  
K. Higashimine ◽  
N. Otsuka
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Series Of Experiments

A series of experiments were performed to explore the growth of InN by Molecular Beam Epitaxy (MBE). The growth conditions were optimized based on the study of RHEED during growth and InN dissociation experiments. Characterization of the InN thin films were performed by various techniques such as TEM and XRD.

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