Superconducting and spin-dependent tunneling using native oxide barriers on CoFe thin films

2000 ◽  
Vol 61 (1) ◽  
pp. 68-71 ◽  
Author(s):  
C. L. Platt ◽  
A. S. Katz ◽  
E. P. Price ◽  
R. C. Dynes ◽  
A. E. Berkowitz
Keyword(s):  
Thin Films ◽  
Native Oxide ◽  
Oxide Barriers

Polycrystalline GeC Thin Films Deposited Using a Unique Hollow Cathode Sputtering Technique

2005 ◽  
Vol 862 ◽  
Author(s):  
R. J. Soukup ◽  
N. J. Ianno ◽  
J. S. Schrader ◽  
V. L. Dalal
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Hollow Cathode ◽  
Growth Conditions ◽  
Group Iv ◽  
Native Oxide ◽  
Cathode Sputtering ◽  
Si Substrates ◽  
New Material ◽  
Equilibrium Growth

AbstractExperimental results on thin films of the new material GexC1-x, deposited by a unique dual plasma hollow cathode sputtering technique are presented. The mostimportant contribution of this work is that it shows that by using non-equilibrium growth conditions resulting from the hollow cathode technique, one can grow Group IV materials which cannot otherwise be grown using normal CVD or MBE processes. The sputtering is accomplished by igniting a dc plasma in the Ar and H2 gases which are fed through Ge and C nozzles.The GeC films are grown on etched Si (100), on Si with the native oxide and on glass. The films grown on glass were quite disordered, but the films grown on both types of Si substrates were very ordered in nature. This order has been characterized using Xray diffraction (XRD) and Raman spectroscopy.Films with as much as 8% C have been deposited. In order to produce useful GexC1-x films, the C must bond to the Ge at lattice sites. Evidence of this desired GeC bond has been seen using Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and XRD.

Interfacial Effects on the Premature Failure of Polycrystalline Silicon Structural Films

2002 ◽  
Vol 741 ◽  
Author(s):  
C.L. Muhlstein ◽  
E.A. Stach ◽  
R.O. Ritchie
Keyword(s):  
Thin Films ◽  
Reaction Layer ◽  
Polycrystalline Silicon ◽  
Ambient Air ◽  
Native Oxide ◽  
Small Scale ◽  
Native Oxide Layer ◽  
Silica Layer ◽  
Premature Failure ◽  
Structural Applications

ABSTRACTAlthough bulk silicon is not known to be susceptible to cyclic fatigue, micron-scale structures made from mono and polycrystalline silicon films are vulnerable to degradation by fatigue in ambient air environments. Such silicon thin films are used in small-scale structural applications, including microelectromechanical systems (MEMS), and display “metal-like” stress-life (S/N) fatigue behavior in room temperature air environments. Previously, the authors have observed fatigue lives in excess of 1011 cycles at high frequency (∼40 kHz), fully-reversed stress amplitudes as low as half the fracture strength using a surface micromachined, resonant-loaded, fatigue characterization structures. Stress-life fatigue, transmission electron microscopy, infrared microscopy, and numerical models were used to establish that the mechanism of the fatigue failure of thin-film silicon involves the sequential oxidation and environmentally-assisted crack growth solely within the native silica layer, a process that we term “reaction-layer fatigue”. Only thin films are susceptible to such a failure mechanism because the critical crack size for catastrophic failure of the entire silicon structure can be exceeded by a crack solely within the native oxide layer. The importance of the interfacial geometry on the mechanics of the reaction-layer fatigue mechanism is described.

Surface Characteristics, Etching Behaviors and Chemicalmechanical Polishing of Aluminum Alloy thin Films

1997 ◽  
Vol 477 ◽  
Author(s):  
Wei-Tsu Tseng ◽  
Jun Wu ◽  
Yee-Shyi Chang
Keyword(s):  
Thin Films ◽  
Alloy Composition ◽  
Surface Characteristics ◽  
Corrosion Current ◽  
Native Oxide ◽  
Al Alloy ◽  
Abrasive Particles ◽  
Mechanical Abrasion ◽  
Underlying Mechanisms ◽  
Auxiliary Role

ABSTRACTEtching behaviors of various Al alloy thin films in H2O2-based acidic etchants are investigated in this study. The pH and H2O2 content in the etchant are varied in order to simulate the case where Al thin films are subject to chemical-mechanical polishing (CMP) using slurries of different compositions. Corrosion current and thickness of the native oxide on pure-Al, AI-1%Si, Al-0.5%Cu, AI-1%Si-0.5%Cu, and AI-1%Cu thin films are determined from Tafel and ESCA analyses respectively. Comparisons between etch rate and CMP polish rate data suggest that Al-CMP removal process depends strongly on the chemical reactions by the oxidizer (slurry). Mechanical abrasion by the abrasive particles plays only an auxiliary role during Al CMP. In addition, alloy composition (% Si and % Cu) influence both etching and polishing behaviors to a great extent. The underlying mechanisms for etching and polishing are discussed.

Structural, Magnetic and Magneto-tranport Properties of Reactive-sputtered Fe3O4 Thin Films

2010 ◽  
Vol 1250 ◽  
Author(s):  
Xinghua Wang ◽  
Sarjoosing Goolaup ◽  
Peng Ren ◽  
Wen Siang Lew
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
Native Oxide ◽  
X Ray Diffraction ◽  
Verwey Transition ◽  
Electrical Measurements ◽  
Metal Insulator ◽  
X Ray ◽  
Sample Measurement

AbstractThin films of magnetite (Fe3O4) are grown on a single-crystal Si/SiO2 (100) substrate with native oxide using DC reactive sputtering technique at room tempreture (RT) and 300C. The x-ray diffraction(XRD) result shows the thermal energy during deposition enhances the crystallization of the Fe3O4 and x-ray photoelectron spectroscopy confirms the film deposited at 300C is single-phase Fe3O4 while the film deposited at RT is mostly ν-Fe2O3. The electrical measurements show that the resistivity of the Fe3O4 film increases exponentially with decreasing temperature, and exhibit a sharp metal-insulator transition at around 100 K, indicating the Verwey transition feature. The saturation magnetization Ms of Fe3O4 film measured by vibrating sample measurement (VSM) at RT was found to be 445 emu/cm3.

Molecular Level Characterization of Thin Paraffinic Films Using NEXAFS Spectroscopy

1993 ◽  
Vol 307 ◽  
Author(s):  
Paul A. Stevens ◽  
David J. Martella
Keyword(s):  
Thin Films ◽  
Phenyl Ring ◽  
Molecular Level ◽  
Van Der Waals ◽  
Intermolecular Forces ◽  
Native Oxide ◽  
X Ray ◽  
Nexafs Spectroscopy ◽  
Surface Normal ◽  
Repulsive Forces

ABSTRACTBecause near edge X-ray absorption fine structures (NEXAFS) are due to dipole transitions from core levels to unoccupied molecular orbitals, it is an ideal technique for obtaining molecular level information about the orientations of ordered species. Such information is important in assessing the relative importance of various intermolecular forces. For example in long chain molecules with bulky functional groups it is not clear a priori whether the attractive van der Waals forces will overcome the repulsive steric interactions to allow for ordering in thin films. To investigate this we have performed C-K edge NEXAFS spectroscopy studies of thin films of the paraffinic molecules C36H74 and (C18H37)2(NCO)C6H4CO2−+NH2(C18H37)2. The films were grown on a Si(111) surface covered with a native oxide. For the normal alkane, the spectra are dominated by three resolvable (Δhυ≈0.5 eV) features: one (C-H)* peak and two σ*(C-C) peaks. The polarization dependence of these peaks indicates that sub-250 Å C36H74 films have the chains of the molecules aligned along the surface normal. For ≈ 2000 Å films the molecular axes are inclined at angle of 32° with respect to the surface normal, in agreement with the crystalline structure determined by X-ray diffraction. In addition to the major structures of the alkane chains, the C-K NEXAFS of (C18H37)2(NCO)C6H4CO2−+NH2(C18H37)2 has a distinct π* peak due to the phenyl ring. Analysis of these resonances indicates that the C-C chains are also aligned along the surface normal, while the phenyl ring is inclined at an angle of 42° with respect to the normal. In conclusion NEXAFS spectroscopy has been used to show that, for the molecules studied, the attractive van der Waals interactions dominate the repulsive forces thus allowing the molecules to orient with their chains aligned along the surface normal in thin films formed on native oxide covered Si(111).

scholarly journals Optimization of Parameters and Microstructural Properties of Ba0.5Sr0.5Co0.8Fe0.2O3-δ Thin Films Grown by Pulsed Laser Deposition (PLD)

2014 ◽  
Vol 17 (4) ◽  
pp. 257-263
Author(s):  
Saša Zeljković ◽  
Toni Ivas ◽  
Anna Infortuna ◽  
Ludwig J. Gauckler
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Columnar Structure ◽  
Laser Deposition ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Microstructural Properties ◽  
Optimization Of Parameters

Ba0.5Sr0.5Co0.8Fe0.2O3 − δ thin films were grown by pulsed laser deposition (PLD) in the temperature range from room temperature (RT) to 1073 K and at oxygen pressures from 6.66 to 39.99 Pa in order to produce dense defect-free thin films. Si with a native oxide layer and MgO were used as the substrate materials. The structure of the thin films was highly dependent on substrate temperature, material and oxygen partial pressure, leading to formation of different microstructures – pores, cracks, columnar and fibrous grains. Cracks and delamination of the thin films were observed in dense layers at higher temperatures, while this was not the case with the columnar thin films. Differences in thermal expansion coefficient, phase transformation and oxygen non-stoichiometry of BSCF are possible explanations for the cracking of the dense thin films. Thin films with a columnar structure are positively influenced by annealing inducing grain growth and densification.

Depression of the Glass Transition Temperature in Ultra-Thin, Grafted Polystyrene Films

1994 ◽  
Vol 366 ◽  
Author(s):  
J. L. Keddie ◽  
R. A. L. Jones
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Ultrathin Films ◽  
Native Oxide

ABSTRACTWe have used ellipsometry to measure the glass transition temperature (Tg) of ultrathin films of polystyrene (PS) (less than 10 nm thick) obtained by grafting PS-COOH on the native oxide of Si. We find that Tg in these ultra-thin films is depressed from the bulk value by as much as, 35 K. This is in qualitative accord with our earlier results on thicker non-grafted films of PS.

Metastable Pyrochlore Structures in Sol Gel Spin Coated Lead Titanate Thin Films on Silicon Substrate

1991 ◽  
Vol 230 ◽  
Author(s):  
Jeon-Kook Lee ◽  
Hyung-Jin Jung ◽  
Chong-Hee Kim
Keyword(s):  
Thin Films ◽  
Silicon Substrate ◽  
Spin Coating ◽  
Lead Titanate ◽  
Random Network ◽  
Sol Gel ◽  
Pyrochlore Structure ◽  
Native Oxide ◽  
Silicon Substrates ◽  
Heat Treated

AbstractHigh quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2 ' area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 500°C in films with thickness above 0.36μm.Metastable pyrochlore structures were observed in films with thickness of 0.16,μm when heat treated at 500 and 600 °C. But these structure did not appear in films with thickness of 0.36μm.The thickness dependencein crystal structure of films was studied by varing the substrate condition and analyzing the interface between the.film and. substrate. In native oxide films on silicon substrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide (cubic property in random network structure).

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