Epitaxial Single Crystalline Ferrite Films for High Frequency Applications

1995 ◽  
Vol 401 ◽  
Author(s):  
Y. Suzuki ◽  
R. B. Van Dover ◽  
V. Korenivski ◽  
D. Werder ◽  
C. H. Chen ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Exchange Coupling ◽  
Spinel Ferrite ◽  
Structural Similarity ◽  
Tem Analysis ◽  
Lattice Match ◽  
Single Crystalline ◽  
Consistent Picture ◽  
Ferrite Films ◽  
The Individual

AbstractThe successful growth of single crystal ferrites in thin film form is an important step towards their future incorporation into integrated circuits operating at microwave frequencies. We have successfully grown high quality single crystalline spinel ferrite thin films of (Mn, Zn)Fe2O4 and CoFe2O4 on (100) and (110) SrTiO3 and MgAl2O4 at low temperature. These ferrite films are buffered with spinel structure layers that are paramagnetic at room temperature. In contrast to ferrite films grown directly on the substrates, ferrite films grown on buffered substrates exhibit excellent crystallinity and bulk saturation magnetization values, thus indicating the importance of lattice match and structural similarity between the film and the immediately underlying layer. X-ray, RBS, AFM and TEM analysis provide a consistent picture of the structural properties of these ferrite films. We then use this technique to grow exchange-coupled bilayers of single crystalline CoFe2O4 and (Mn, Zn)Fe2O4. In these bilayers, we observe strong exchange coupling across the interface that is similar in strength to the exchange coupling in the individual layers.

Formation of Large, Orientation-Controlled, Nearly Single Crystalline Si Thin Films on SiO2 Using Contact Printing of Rolled and Annealed Nickel Tapes

2003 ◽  
Vol 762 ◽  
Author(s):  
Hwang Huh ◽  
Jung H. Shin
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
High Resolution ◽  
Amorphous Silicon ◽  
Tem Analysis ◽  
Contact Printing ◽  
Single Crystalline ◽  
High Resolution Tem ◽  
Lateral Crystallization ◽  
Si Films

AbstractAmorphous silicon (a-Si) films prepared on oxidized silicon wafer were crystallized to a highly textured form using contact printing of rolled and annealed nickel tapes. Crystallization was achieved by first annealing the a-Si film in contact with patterned Ni tape at 600°C for 20 min in a flowing forming gas (90 % N2, 10 % H2) environment, then removing the Ni tape and further annealing the a-Si film in vacuum for2hrsat600°C. An array of crystalline regions with diameters of up to 20 μm could be formed. Electron microscopy indicates that the regions are essentially single-crystalline except for the presence of twins and/or type A-B formations, and that all regions have the same orientation in all 3 directions even when separated by more than hundreds of microns. High resolution TEM analysis shows that formation of such orientation-controlled, nearly single crystalline regions is due to formation of nearly single crystalline NiSi2 under the point of contact, which then acts as the template for silicide-induced lateral crystallization. Furthermore, the orientation relationship between Si grains and Ni tape is observed to be Si (110) || Ni (001)

Room-temperature spin glass and its photocontrol in spinel ferrite films

2000 ◽  
Vol 77 (24) ◽  
pp. 4016-4018 ◽  
Author(s):  
Yuji Muraoka ◽  
Hitoshi Tabata ◽  
Tomoji Kawai
Keyword(s):  
Spin Glass ◽  
Room Temperature ◽  
Spinel Ferrite ◽  
Ferrite Films

scholarly journals PROXIMITY EFFECTS AND CURIE TEMPERATURE ENHANCEMENT IN Co/EuS AND Fe/EuS MULTILAYERS

SPIN ◽  
2012 ◽  
Vol 02 (04) ◽  
pp. 1250016 ◽  
Author(s):  
B. LEWITZ ◽  
A. STRAUB ◽  
V. KAPAKLIS ◽  
P. POULOPOULOS ◽  
A. DELIMITIS ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Exchange Coupling ◽  
Proximity Effects ◽  
Antiferromagnetic Exchange ◽  
Coupling Constant ◽  
Polycrystalline Structure ◽  
Individual Layer ◽  
Temperature Enhancement ◽  
The Individual ◽  
Almost Continuous

Two identical Co/EuS and Fe/EuS multilayers of six periods each and with individual layers of about 4 nm thick are grown by e-beam evaporation under ultrahigh vacuum conditions. The films show polycrystalline structure with a grain size limited by the individual layer thickness. Both multilayers consist of almost continuous layers with some roughness. The surface peak-to-peak roughness is about 4–5 nm. Magnetization measurements and calculations of the loops based on a Stoner–Wohlfarth-like model allow us to determine the direct antiferromagnetic exchange coupling constant between the 3d metal and EuS at 5 K. Both samples show strong enhancement of the Curie temperature of EuS up to at least 50 K with a EuS magnetization tail, which persists up to about 100 K. The J = 7/2 character of the EuS layers is shown to be responsible for the large Curie temperature enhancement.

Single-Crystalline and Bamboo Al Lines Fabricated by Graphoepitaxy: Microstructure and 1/f Noise Measurements

1996 ◽  
Vol 428 ◽  
Author(s):  
Marc J.C. Van Den Homberg ◽  
A. H. Verbruggen ◽  
P. F. A. Alkemade ◽  
S. Radelaar
Keyword(s):  
Integrated Circuits ◽  
Grain Boundaries ◽  
Low Noise ◽  
Dc Magnetron Sputtering ◽  
Rapid Thermal Anneal ◽  
Single Crystalline ◽  
Noise Measurements ◽  
Scaling Down ◽  
Sputter Deposited

AbstractThe continuing scaling-down of integrated circuits leads to increased metallization reliability problems, especially electromigration. We used 1/f noise measurements to study the relation between electromigration and microstructure. These measurements are very sensitive to the microstructural attributes, such as grain boundaries and dislocations. Al lines were grown by graphoepitaxy: First, a pure Al film was grown by dc magnetron sputtering on a groove pattern etched into a SiO2 substrate. The growth was then followed by an in situ rapid thermal anneal that resulted in a complete filling of the grooves with Al. These Al lines were carefully characterized with SEM and Backscatter Kikuchi Diffraction. Depending on the presence of a temperature gradient during the anneal, the lines were either nearly single-crystalline or bamboo with one grain per ∼ 3 μm. The resistivity was ∼ 2.8 μΩcm, only slightly higher than for bulk Al. We measured the 1/f noise with the two-channel ac technique at RT. We found in both bamboo as well as the single-crystalline lines a very low noise intensity; a factor two lower than in conventionally sputter deposited and annealed Al lines. No clear difference between the noise spectra of the bamboo and the single-crystalline lines was observed. We concluded that grain boundaries are not the only contributor to 1/f noise; other types of defects must play a role as well.

Study of Porous Silica Based Films as Low-k Dielectric Material and their Interface with Copper Metallization

2002 ◽  
Vol 716 ◽  
Author(s):  
Ilanit Fisher ◽  
Wayne D. Kaplan ◽  
Moshe Eizenberg ◽  
Michael Nault ◽  
Timothy Weidman
Keyword(s):  
Integrated Circuits ◽  
Dielectric Material ◽  
Hydrogen Plasma ◽  
Porous Silica ◽  
Film Deposition ◽  
Copper Metallization ◽  
High Porosity ◽  
Tem Analysis ◽  
Chip Technology ◽  
Low K

AbstractThe success of future gigascale integrated circuits (IC) chip technology depends critically upon the reduction of the interconnects RC delay time. This calls for the development of new low dielectric constant (low-k) insulators, and for work on their integration with lower resistivity copper metallization.A porous silica based film prepared by surfactant templated self-assembly spin-on deposition (SOD) is an attractive candidate as a low-k material. In this research we have studied the structure, chemical composition and bonding of the film and its interface with copper metallization. The decomposition and vaporization of the surfactant in the last step of film deposition resulted in a film with an amorphous structure, as determined by XRD and TEM analysis. Its high porosity (35-58%) was confirmed by XRR and RBS measurements. XPS analysis of the Si2p transition indicated three types of bonding: Si-O, O-Si-C and Si-C. The bonding characteristics were also investigated by FTIR analysis. The effect of a hydrogen plasma post-treatment process on the film topography and bonding was determined by AFM and XPS, respectively. It was found that direct H2 plasma exposure significantly affected the surface roughness of the film and type of chemical bonding. The structure and properties of various PECVD deposited capping layers were also studied, as was the interface between the porous dielectric and Ta, TaxN and Cu (PVD deposited films) after annealing at 200-700°C in vacuum environment for 30 min. At temperatures up to 500°C, no significant diffusion of Cu or Ta into the porous film was detected, as determined by RBS. No copper penetration was detected up to 700°C, according to AES and SIMS analysis. However, at 700°C copper dewetting occurred when it was deposited directly on the porous silica based film.

Pseudomorphic spinel ferrite films with perpendicular anisotropy and low damping

2018 ◽  
Vol 113 (8) ◽  
pp. 082404 ◽  
Author(s):  
R. C. Budhani ◽  
Satoru Emori ◽  
Zbigniew Galazka ◽  
Benjamin A. Gray ◽  
Maxwell Schmitt ◽  
...  
Keyword(s):  
Spinel Ferrite ◽  
Perpendicular Anisotropy ◽  
Ferrite Films

scholarly journals Ego-zones: non-symmetric dependencies reveal network groups with large and dense overlaps

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Milos Kudelka ◽  
Eliska Ochodkova ◽  
Sarka Zehnalova ◽  
Jakub Plesnik
Keyword(s):  
Network Structure ◽  
Real World ◽  
Ground Truth ◽  
Structural Similarity ◽  
Global Network ◽  
Overlapping Communities ◽  
Detection Algorithms ◽  
First Case ◽  
New Perspective ◽  
The Individual

Abstract The existence of groups of nodes with common characteristics and the relationships between these groups are important factors influencing the structures of social, technological, biological, and other networks. Uncovering such groups and the relationships between them is, therefore, necessary for understanding these structures. Groups can either be found by detection algorithms based solely on structural analysis or identified on the basis of more in-depth knowledge of the processes taking place in networks. In the first case, these are mainly algorithms detecting non-overlapping communities or communities with small overlaps. The latter case is about identifying ground-truth communities, also on the basis of characteristics other than only network structure. Recent research into ground-truth communities shows that in real-world networks, there are nested communities or communities with large and dense overlaps which we are not yet able to detect satisfactorily only on the basis of structural network properties.In our approach, we present a new perspective on the problem of group detection using only the structural properties of networks. Its main contribution is pointing out the existence of large and dense overlaps of detected groups. We use the non-symmetric structural similarity between pairs of nodes, which we refer to as dependency, to detect groups that we call zones. Unlike other approaches, we are able, thanks to non-symmetry, accurately to describe the prominent nodes in the zones which are responsible for large zone overlaps and the reasons why overlaps occur. The individual zones that are detected provide new information associated in particular with the non-symmetric relationships within the group and the roles that individual nodes play in the zone. From the perspective of global network structure, because of the non-symmetric node-to-node relationships, we explore new properties of real-world networks that describe the differences between various types of networks.

Nanocomposites of metallic copper and spinel ferrite films: Growth and self-assembly of copper particles

2005 ◽  
Vol 493 (1-2) ◽  
pp. 49-53 ◽  
Author(s):  
Emmanuelle Mugnier ◽  
Isabelle Pasquet ◽  
Antoine Barnabé ◽  
Lionel Presmanes ◽  
Corine Bonningue ◽  
...  
Keyword(s):  
Self Assembly ◽  
Spinel Ferrite ◽  
Metallic Copper ◽  
Copper Particles ◽  
Ferrite Films

Spinel ferrite films by a novel solution process for high frequency applications

2010 ◽  
Vol 123 (1) ◽  
pp. 16-19 ◽  
Author(s):  
A.K. Subramani ◽  
K. Kondo ◽  
M. Tada ◽  
M. Abe ◽  
M. Yoshimura ◽  
...  
Keyword(s):  
High Frequency ◽  
Spinel Ferrite ◽  
Solution Process ◽  
Ferrite Films

A Soft Solution Processing Technique for Preparing Ferrite Films and Their Applications

MRS Bulletin ◽  
2000 ◽  
Vol 25 (9) ◽  
pp. 51-55 ◽  
Author(s):  
Masanori Abe
Keyword(s):  
Integrated Circuits ◽  
Chemical Process ◽  
Processing Technique ◽  
Solution Processing ◽  
Ferrite Film ◽  
Spinel Type ◽  
One Step ◽  
Wet Chemical ◽  
Ferrite Films ◽  
Film Synthesis

“Ferrite plating” is a typical “soft solution processing” (SSP) application; it enables the formation of oxide ferromagnetic films from an aqueous solution atT24−100°C under atmospheric pressure. Using ferrite plating, we can grow crystallized ferrite films of spinel-type (MFe)3O4(where M = Fe, Co, Ni, Zn, Al, Cr, etc.) in one step, requiring no heat treatment. This opens the door to fabricating novel ferritefilm devices using substrates of such nonheat-resistant materials as plastics and GaAs integrated circuits; conventional ferrite-film preparation techniques, such as sputtering, vacuum evaporation, molecularbeam epitaxy, liquid-phase epitaxy, and so on, require high temperatures (>∼600°C) for the crystallization of ferrites, which deteriorates the non-heat-resistant substrates. Ferrite plating is a unique technique that allows us to synthesize ferrite “films” by means of a wet chemical process. There are many techniques, for synthesizing ferrite “particles” from aqueous solutions, but no technique, to our knowledge, enables ferrite-film synthesis by a wet chemical process.

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