scholarly journals Evidence of weak Anderson localization revealed by the resistivity, transverse magnetoresistance and Hall effect measured on thin Cu films deposited on mica

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eva Díaz ◽  
Guillermo Herrera ◽  
Simón Oyarzún ◽  
Raul C. Munoz
Keyword(s):  
Integrated Circuits ◽  
Hall Effect ◽  
Electron Scattering ◽  
Anderson Localization ◽  
Mean Free Path ◽  
Negative Magnetoresistance ◽  
Cu Films ◽  
Transverse Magnetoresistance ◽  
The Mean ◽  
Electron Mean Free Path

AbstractWe report the resistivity of 5 Cu films approximately 65 nm thick, measured between 5 and 290 K, and the transverse magnetoresistance and Hall effect measured at temperatures 5 K < T < 50 K. The mean grain diameters are D = (8.9, 9.8, 20.2, 31.5, 34.7) nm, respectively. The magnetoresistance signal is positive in samples where D > L/2 (where L = 39 nm is the electron mean free path in the bulk at room temperature), and negative in samples where D < L/2. The sample where D = 20.2 nm exhibits a negative magnetoresistance at B < 2 Tesla and a positive magnetoresistance at B > 3 Tesla. A negative magnetoresistance in Cu films has been considered evidence of charge transport involving weak Anderson localization. These experiments reveal that electron scattering by disordered grain boundaries found along L leads to weak Anderson localization, confirming the localization phenomenon predicted by the quantum theory of resistivity of nanometric metallic connectors. Anderson localization becomes a severe obstacle for the successful development of the circuit miniaturization effort pursued by the electronic industry, for it leads to a steep rise in the resistivity of nanometric metallic connectors with decreasing wire dimensions (D < L/2) employed in the design of Integrated Circuits.

Transverse magnetoresistance, Hall mobility and Hall constant of thin Cu films deposited onto cleaved mica: Evidence of weak Anderson localization.

2021 ◽  
Author(s):  
Eva Díaz ◽  
Guillermo Herrera ◽  
Simón Oyarzún ◽  
Raul Munoz
Keyword(s):  
Integrated Circuits ◽  
Electron Scattering ◽  
Anderson Localization ◽  
Mean Free Path ◽  
Negative Magnetoresistance ◽  
Hall Constant ◽  
Cu Films ◽  
Transverse Magnetoresistance ◽  
The Mean ◽  
Electron Mean Free Path

Abstract We report the resistivity of 5 Cu films approximately 65 nm thick, measured between 5 K and 290 K, and the transverse magnetoresistance and Hall effect measured at temperatures 5 K< T<50 K. The mean grain diameters are D=(8.9, 9.8, 20.2, 31.5, 34.7) nm, respectively. The magnetoresistance signal is positive in samples where D>L/2 (where L=39 nm is the electron mean free path in the bulk at room temperature), and negative in samples where D<L/2. The sample where D=20.2 nm exhibits a negative magnetoresistance at B < 2 Tesla and a positive magnetoresistance at B > 2 Tesla. A negative magnetoresistance in Cu films has been considered evidence of charge transport involving weak Anderson localization. These experiments reveal that electron scattering by disordered grain boundaries found along L leads to weak Anderson localization, confirming the localization phenomena predicted by the quantum theory of resistivity of nanometric metallic connectors. Anderson localization becomes a severe obstacle for the successful development of the circuit miniaturization effort pursued by the electronic industry, for it leads to a steep rise in the resistivity of nanometric metallic connector with decreasing wire dimensions (D<L/2) employed in the design of Integrated Circuits.

Interplay Between Thermoelectric and Thermionic Effects in Heterostructures

2000 ◽  
Author(s):  
Taofang Zeng ◽  
Gang Chen
Keyword(s):  
Film Thickness ◽  
Free Path ◽  
Thermionic Emission ◽  
Approximate Solutions ◽  
Mean Free Path ◽  
Boltzmann Transport ◽  
Thermoelectric Effects ◽  
Double Heterojunction ◽  
The Mean ◽  
Electron Mean Free Path

Abstract When electrons sweep through a double-heterojunction structure, there exist thermionic effects at the junctions and thermoelectric effects in the film. While both thermoelectric and thermionic effects have been studied for refrigeration and power generation applications separately, their interplay in heterostructures is not understood. This paper establishes a unified model including both thermionic and thermoelectric processes based on the Boltzmann transport equation for electrons, and the nonequilibrium interaction between electrons and phonons. Approximate solutions are obtained, leading to the electron temperature and Fermi level distributions inside heterostructures and discontinuities at the interfaces as a consequence of the highly nonequilibrium transport when the film thickness is much smaller than the electron mean free path. It is found that when the film thickness is smaller than the mean free path of electrons, the transport of electrons is controlled by thermionic emission. The coexistence of thermoelectric and thermionic effects may increase the power factor when the electron mean free path is comparable to the film thickness.

Heat Transfer and Thermoelectric Voltage at Metallic Point Contacts

1993 ◽  
Vol 115 (3) ◽  
pp. 757-762 ◽  
Author(s):  
P. E. Phelan ◽  
O. Nakabeppu ◽  
K. Ito ◽  
K. Hijikata ◽  
T. Ohmori ◽  
...  
Keyword(s):  
Temperature Drop ◽  
Point Contact ◽  
Thermal Characteristics ◽  
Mean Free Path ◽  
Contact Radius ◽  
Point Contacts ◽  
Plate Temperature ◽  
Thermoelectric Voltage ◽  
The Mean ◽  
Electron Mean Free Path

Metallic point contacts have been extensively studied from the viewpoint of their interesting, and often nonlinear, electrical properties. Their thermal characteristics, however, have largely been ignored, even though they show great potential as microscale temperature sensors. It has been previously demonstrated that when a temperature drop exists across a point contact consisting of two identical metals, a thermoelectric voltage can be generated, provided the mean contact radius is comparable in size to the electron mean free path. In the present experimental study, a point contact is formed by pressing a sharply etched Ag whisker against either an Ag or a Cu flat plate. In addition to confirming the previous results, the feasibility of using such a point contact is demonstrated by calibrating the voltage output against the nondimensionalized plate temperature. Furthermore, the thermoelectric voltage at an Ag–Cu point contact is also presented, showing that a point contact made from dissimiliar metals is even more promising than one made from identical materials. Finally, the point-contact thermal resistance is shown to depend nonlinearly on the electrical resistance, or contact area, and on the temperature drop.

Deposition and anneal behavior of Al-1.5%Cu films: TEM characterization

1991 ◽  
Vol 49 ◽  
pp. 884-885
Author(s):  
N. David Theodore ◽  
Mike Dreyer ◽  
Charles Varker
Keyword(s):  
Integrated Circuits ◽  
Imaging Techniques ◽  
Dark Field ◽  
Time To Failure ◽  
Plan View ◽  
Cu Films ◽  
Transmission Electron ◽  
Grain Size Distributions ◽  
The Mean ◽  
Mean Time

Al-1.5%Cu materials are of interest for interconnect-metallization in semiconductor integrated-circuits. It is known from the literature that the mean-time-to-failure (MTF) due to electromigration of the Al-1.5%Cu interconnects depends on the microstructure of the materials. A correlation is seen for instance between grain-size distributions in the material and the MTF. Uniform large-grained distributions improve lifetime. The present study evaluated the microstructure of Al-1.5%Cu films deposited and annealed under different conditions.Al-1.5%Cu films had been deposited at 25°C and at 300°C; the layers had then been annealed at 300°C for 17 hours, prior to TEM investigation. Plan-view TEM specimens were prepared in the 100 substrategeometry, and cross-section TEM specimens were prepared in the 110 substrate-geometry. These were then analyzed using bright-field and dark-field TEM imaging techniques. A JEOL JEM 200CX transmission electron microscope was used for the investigation, operating at 200 kV.

MAGNETORESISTANCE AND HALL EFFECT OF TWO-DIMENSIONAL 2H-NbSe2

2005 ◽  
Vol 19 (01n03) ◽  
pp. 275-279 ◽  
Author(s):  
LINJUN LI ◽  
JINGQIN SHEN ◽  
ZHUAN XU ◽  
HONGTAO WANG
Keyword(s):  
Hall Effect ◽  
Density Wave ◽  
Mean Free Path ◽  
Band Model ◽  
Two Dimensional ◽  
Superconducting Transition ◽  
Drastic Increase ◽  
Steep Decrease ◽  
The Mean ◽  
Magneto Resistance

Single crystals of two-dimensional 2 H - NbSe 2, which undergo superconducting transition at Tc=7.1 K and charge-density wave (CDW) transition at TCDW=30 K , were synthesized. The resistance residual ratio (RRR=R(300 K )/R(8 K )) of the samples from different batches varies from 10 to 30, but the superconducting properties hardly change with RRR. The magneto-resistance (MR)is generally small and its temperature and field dependence of MR violate the Kohler's rule that holds for many conventional metals, indicating that the scattering times of charge carriers are no longer isotropic. The steep decrease of Hall coefficient RH below 50 K can be interpreted by the drastic increase of the mean-free-path of electron type charge carrier. The influence of CDW transition on the resistivity and Hall effect is discussed in a two-band model.

EFFECTS OF CORRELATIONS AND DISORDER IN QUANTUM WIRES

1999 ◽  
Vol 13 (05n06) ◽  
pp. 489-495
Author(s):  
D. NEILSON ◽  
J. S. THAKUR
Keyword(s):  
Electron Scattering ◽  
Quantum Wires ◽  
Mean Free Path ◽  
Static Structure Factor ◽  
Correlation Effects ◽  
Static Structure ◽  
Scattering Rate ◽  
Effects Of Disorder ◽  
Electron Correlation Effects ◽  
The Mean

We calculate electron-electron correlation effects in a one-dimensional electron liquid at low densities using the self-consistent scheme of Singwi, Tosi, Land and Sjölander (STLS). We determine the static structure factor S(q) and plasmon dispersion ω pl (q) for different electron densities. We also include the effects of disorder and calculate the dependence of correlation effects on the electron scattering rate off disorder. Using the scattering rate γ we determine transport properties like the mean-free path, the peak mobility and the boundary between weak and strong localisation phases. We note a relation between the peak mobility and this boundary.

scholarly journals Depth Resolution Dependence on Sample Thickness and Incident Energy in On-Axis Transmission Kikuchi Diffraction in Scanning Electron Microscope (SEM)

2017 ◽  
Vol 23 (6) ◽  
pp. 1096-1106 ◽  
Author(s):  
Etienne Brodu ◽  
Emmanuel Bouzy
Keyword(s):  
Incident Energy ◽  
Depth Resolution ◽  
Mean Free Path ◽  
Total Sample ◽  
Sample Thickness ◽  
Crystal Sample ◽  
Continuous Absorption ◽  
Orientation Maps ◽  
The Mean ◽  
Electron Mean Free Path

AbstractTransmission Kikuchi diffraction is an emerging technique aimed at producing orientation maps of the structure of materials with a nanometric lateral resolution. This study investigates experimentally the depth resolution of the on-axis configuration, via a twinned silicon bi-crystal sample specifically designed and fabricated. The measured depth resolution varies from 30 to 65 nm in the range 10–30 keV, with a close to linear dependence with incident energy and no dependence with the total sample thickness. The depth resolution is explained in terms of two mechanisms acting concomitantly: generation of Kikuchi diffraction all along the thickness of the sample, associated with continuous absorption on the way out. A model based on the electron mean free path is used to account for the dependence with incident energy of the depth resolution. In addition, based on the results in silicon, the use of the mean absorption coefficient is proposed to predict the depth resolution for any atomic number and incident energy.

Perpendicular Resistance of Co/Cu Multilayers Prepared by Molecular Beam Epitaxy

1995 ◽  
Vol 384 ◽  
Author(s):  
N.J. List ◽  
W.P. Pratt ◽  
M.A. Howson ◽  
J. Xu ◽  
M.J. Walker ◽  
...  
Keyword(s):  
Free Path ◽  
Spin Diffusion ◽  
Mean Free Path ◽  
Ferromagnetic Structure ◽  
Order Of Magnitude ◽  
The Mean ◽  
Electron Mean Free Path ◽  
Determining Factor ◽  
Second Peak ◽  
Key Parameter

ABSTRACTResults are presented of the magnetoresistance of MBE-grown (111) Co/Cu multilayers measured with the current perpendicular to the plane of the layers (CPP). Although for measurements made with the more common geometry of current in the plane of the layers (CIP) there are large differences between the results on samples made by sputtering and those prepared by MBE, for these new CPP data the results on samples made by the two techniques are very much alike. For copper layers with thicknesses between 0.9nm to 6nm the magnetoresistance shows oscillations with copper thickness that were almost non-existent in the earlier CIP data. At the second peak the magnetoresistance in the CPP geometry is an order of magnitude greater than that in the CIP configuration. Although the interfaces in these samples have been shown to be very sharp, they appear to form a mosaic structure with the antiferromagnetic regions embedded in a ferromagnetic structure. It is argued that for CIP measurements the GMR is greatly reduced by these ferromagnetic correlations over lengthscales long compared to the electron mean free path. For CPP measurements, on the other hand, it is the spin diffusion length that is the determining factor with the mean free path no longer a key parameter and with values of the GMR virtually independent of the growth process.

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