scholarly journals Evolution of the ultrasonic resonance modes in a three-layer structure with change of material and interface adhesion properties

2016 ◽  
Vol 65 (7) ◽  
pp. 074301
Author(s):  
Liu Jing ◽  
Xu Wei-Jiang ◽  
Hu Wen-Xiang
Keyword(s):  
Layer Structure ◽  
Interface Adhesion ◽  
Adhesion Properties ◽  
Resonance Modes ◽  
Ultrasonic Resonance

scholarly journals Microstructure Formation and Mechanical Properties of Multi-Phase Coating by Thermos Plasma Nitriding of Gradient Cu-Ti Films on C61900 Cu Alloy

2021 ◽  
Vol 11 (22) ◽  
pp. 10843
Author(s):  
Yandan Zhu ◽  
Mufu Yan ◽  
Quanli Zhang
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Layer Structure ◽  
Plasma Nitriding ◽  
Ductile Phase ◽  
Adhesion Properties ◽  
Cu Alloy ◽  
Phase Coating ◽  
Multi Phase ◽  
N Compounds

To improve the processing efficiency and the surface properties of C61900 Cu alloy, a gradient Cu-Ti film with a Ti/Cu atom ratio of 7:1, 7:4, and 1:2 was pre-fabricated by the unbalanced magnetron sputtering process and then nitrided by thermos plasma nitriding. The phase structure, elemental composition, and morphology of the modified surface were characterized, and the mechanical properties, including the wear resistance and adhesion properties, were examined. Combining calculation by the first principle method with thermodynamic analysis, the microstructural formation and phase composition of the Cu-Ti-N system were investigated to reveal the mechanism of improved wear resistance, which indicated the possible formation of various Cu-Ti intermetallics and Ti-N compounds. The Al in the C61900 Cu substrate also participated in the generation of the AlCu2Ti compound, which is a ductile phase with good hardness and elastic modulus. Based on the results of a mechanical properties test, it was concluded that an optimized layer structure for the multi-phase coating should include Ti-N compounds as the surface layer and Cu-Ti intermetallics as the intermediate layer.

Copper Oxidation Effect in the EMC/Cu Interfacial Adhesion Improvement for a Novel Copper Interconnection Substrate Application

2018 ◽  
Vol 2018 (1) ◽  
pp. 000161-000166
Author(s):  
Min-Fong Shu ◽  
Yi-Hsiu Tseng
Keyword(s):  
Hydrogen Bonding ◽  
Reaction Mechanism ◽  
Cupric Oxide ◽  
Layer Structure ◽  
Copper Oxidation ◽  
Interface Adhesion ◽  
Oxidation Layer ◽  
Copper Interconnection ◽  
Cu Bonding ◽  
Cu Oxidation

Abstract Copper oxidation structure, cupric oxide (CuO) and cuprous oxide (Cu2O), under Ar/H2 plasma reaction mechanism for the EMC/Cu interface adhesion improvement was studied in this work. This work is utilized TGA to figure out Cu oxidized state and sample preparation, and using plasma treatment Cu oxidation layer to evaluate the EMC/Cu interface adhesion strength by shear testing method. Results show a plasma reduction on Cu oxidation layer provide a better interface adhesion, and the layer structure has a significant composition change, Cu/Cu2O/CuO/EMC → Cu/Cu2O/CuO/Cu2O/EMC. These layer structures were identified by high-resolution TEM mapping with EELS spectrum fitting, it was also verified for CuO reduction to form Cu2O, following the Cu2O hydration would provide much hydrogen-bonding in the EMC/Cu interface. This kind of chain reaction mechanism including CuO reduction and Cu2O hydration was described by 2CuO + H2 → Cu2O +H2O → 2CuOH (hydration molecular). The reaction mechanism of the EMC/Cu bonding has been investigated and verified in this experimental study and our conclusion is that hydrogen bonding on the Cu oxidation layer surface can strengthen the EMC/Cu interface adhesion.

scholarly journals Observation of magnetic droplets in magnetic tunnel junctions

2021 ◽  
Vol 65 (2) ◽  
Author(s):  
Kewen Shi ◽  
Wenlong Cai ◽  
Sheng Jiang ◽  
Daoqian Zhu ◽  
Kaihua Cao ◽  
...  
Keyword(s):  
Materials Science ◽  
Tunnel Junctions ◽  
Layer Structure ◽  
Magnetic Tunnel Junctions ◽  
Spin Torque ◽  
Free Layer ◽  
Resonance Modes ◽  
Power Enhancement ◽  
Highly Nonlinear ◽  
Pinning Field

AbstractMagnetic droplets, a class of highly nonlinear magnetodynamic solitons, can be nucleated and stabilized in nanocontact spin-torque nano-oscillators. Here we experimentally demonstrate magnetic droplets in magnetic tunnel junctions (MTJs). The droplet nucleation is accompanied by power enhancement compared with its ferromagnetic resonance modes. The nucleation and stabilization of droplets are ascribed to the double-CoFeB free-layer structure in the all-perpendicular MTJ, which provides a low Zhang-Li torque and a high pinning field. Our results enable better electrical sensitivity in fundamental studies of droplets and show that the droplets can be utilized in MTJ-based applications and materials science.

scholarly journals On the impedance of a high-frequency capacitive discharge with different excitation methods

2021 ◽  
pp. 33-38
Author(s):  
Sergei Dvinin ◽  
Oleg Sinkevich ◽  
Zafari Kodirzoda ◽  
Davlat Solikhov
Keyword(s):  
Electromagnetic Field ◽  
High Frequency ◽  
Layer Structure ◽  
Metal Layer ◽  
Direct Calculation ◽  
Comsol Multiphysics ◽  
Large Area ◽  
Resonance Modes ◽  
Analytical Formulas ◽  
Ampli Tude

Consideration is given to a low-pressure ( << ) capacitive high-frequency discharge with large-area electrodes when it is excited by an electromagnetic field with a frequency from 13 to 900 MHz. General analytical formulas are obtained for the amplitudes of natural waves and the impedance of the discharge. It is taken into account that the excitation of surface waves and higher nonpropagating modes occurs both due to the axial inhomogeneity of the plasma-metal layer structure and due to edge effects at the electrode cut. The higher ampli-tude of the resonance modes in this case (in comparison with the excitation of the discharge by a TEM wave) leads to a greater irregularity in the dependence of the discharge impedance on the electron density. This conclusion is confirmed by the direct calculation of impedance using the Comsol Multiphysics® software.

Backscattered Electron Imaging of GaAs/AlGaAs Super Lattice Structures with an Ultra-High- Resolution SEM

1988 ◽  
Vol 46 ◽  
pp. 204-205
Author(s):  
Kazumichi Ogura ◽  
Michael M. Kersker
Keyword(s):  
High Resolution ◽  
Layer Structure ◽  
High Sensitivity ◽  
Beam Current ◽  
Electron Beam Current ◽  
Lattice Structures ◽  
Super Lattice ◽  
Different Types ◽  
Backscattered Electron ◽  
Electron Imaging

Backscattered electron (BE) images of GaAs/AlGaAs super lattice structures were observed with an ultra high resolution (UHR) SEM JSM-890 with an ultra high sensitivity BE detector. Three different types of super lattice structures of GaAs/AlGaAs were examined. Each GaAs/AlGaAs wafer was cleaved by a razor after it was heated for approximately 1 minute and its crosssectional plane was observed.First, a multi-layer structure of GaAs (100nm)/AlGaAs (lOOnm) where A1 content was successively changed from 0.4 to 0.03 was observed. Figures 1 (a) and (b) are BE images taken at an accelerating voltage of 15kV with an electron beam current of 20pA. Figure 1 (c) is a sketch of this multi-layer structure corresponding to the BE images. The various layers are clearly observed. The differences in A1 content between A1 0.35 Ga 0.65 As, A1 0.4 Ga 0.6 As, and A1 0.31 Ga 0.69 As were clearly observed in the contrast of the BE image.

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