Comparison Between I/F Noise, High-Resolution Resistometric, and Lifetime Electromigration Studies of AL and AL(SI)

1993 ◽  
Vol 309 ◽  
Author(s):  
J.R. Kraayeveld ◽  
A.H. Verbruggen ◽  
S. Radelaar
Keyword(s):  
Thin Films ◽  
High Resolution ◽  
Room Temperature ◽  
Activation Energies ◽  
Lifetime Measurements ◽  
Noise Measurements ◽  
Electromigration Lifetime ◽  
Local Disorder ◽  
Dc Current

AbstractTo compare the results obtained by 1/f noise, high-resolution resistance and electromigration lifetime measurements, the effect of annealing at 400 °C in forming gas of Al and AI(Si) thin films has been studied. All samples of a given composition have been fabricated simultaneously. Upon annealing, the 1/f noise measured at room temperature decreases by a factor of two whereas the lifetime increases by a factor 3 to 6. The activation energies derived from the 1/f noise and the high-resolution resistance measurements during and after stressing with a DC current are closely correlated and compare well to values reported for lifetime measurements. Comparing the data of the different experiments suggest that the lifetime experiments predominantly probe the presence of weak spots in the films whereas the noise measurements respond more to local disorder.

The Effect of Annealing on the Cu Distribution and AI2Cu Precipitation in Ai(Cu) Thin Films

1993 ◽  
Vol 309 ◽  
Author(s):  
E.G. Colgan ◽  
K.P. Rodbell ◽  
D.R. Vigliotti
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Grain Boundaries ◽  
Low Temperatures ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Precipitate Morphology ◽  
Electromigration Lifetime ◽  
Bamboo Structure ◽  
Anneal Temperature

AbstractThe Cu distribution in AI(Cu) thin films has been examined in blanket and patterned samples as a function of annealing. The Cu concentration in the Al grains, measured at room temperature, closely follows the solubility at the anneal temperature when a high cooling rate is used (-100 or -200°C/min) from the annealing temperature. With fine lines, the room temperature Cu concentration follows the solubility at the anneal temperature only at low anneal temperatures, ≤350°C. With higher temperatureannealing, >400°C, the room temperature Cu concentration in the Al grains was substantially less than the solubility at the anneal temperature. These differences are attributed to the smaller grain size in fine lines, which reduces the distance to grain boundaries. With blanket films, the Θ-phase (Al2Cu) precipitate morphology depends on the Al grain size and annealing temperature. With small Al grains (100-300 nm), the Θ particles are small (100-200 nm) and round whereas with large Al grains (0.5-2μm), the precipitates are long and irregularly shaped. The morphology of the Θ precipitates is constrained by the Al grain size. With fine lines, having a bamboo structure, the Θ precipitates are “wedge” shaped along grain boundaries or span the width of the line. The electromigration lifetime was found to depend strongly on the heat treatment used, an increase of 3X in lifetime was obtained for samples rapidly cooled from a temperature above the solvus curve as compared with samples subjected to additional aging at low temperatures. This is believed to be dueto the different concentrations of Cu in solution and to the size and distribution of Θparticles in the patterned lines.

I/F Noise Measurements in Al-Si, Al-Si-V and Al-Si-V-Pd Alloy Films

1994 ◽  
Vol 338 ◽  
Author(s):  
J.R. Kraayeveld ◽  
R.A. Augur ◽  
A.G. Dirks ◽  
A.H. Verbruggen ◽  
S. Radelaar
Keyword(s):  
Noise Intensity ◽  
Room Temperature ◽  
Test Line ◽  
Alloy Films ◽  
Dc Sputtering ◽  
Pd Alloy ◽  
Noise Measurements ◽  
Electromigration Lifetime ◽  
Si Films

ABSTRACTThe electromigration lifetime of Al-Si (1 at.% Si) can be greatly increased by alloying with V and Pd (0.1 at.% V, 0.1 at.% Pd). This study reports on l/fα (α≈l) noise measurements in Al-Si, Al-Si-V and Al-Si-V-Pd alloy films. Samples were prepared by direct current (DC) sputtering, e-beam lithography and reactive-ion etching. The samples were annealed at 450 °C for 30 min and were not passivated. Test line dimensions were 800μm×l.2μm×0.5μm. 1/f noise was measured by a high-resolution alternating current (AC) bridge technique, which ensured that no electromigration occurred during the measurements. The sample-to-sample variation in normalized 1/f noise intensity for Al-Si, Al-Si-V and, Al-Si-V-Pd, measured at room temperature, was less than 10%. The smallest noise intensities were observed in the Al-Si-V-Pd films. The temperature dependence of the 1/f noise of Al-Si films shows a maximum at 338 K allowing the determination of the activation energy of the noise generating process (Ea = 0.75 eV). Above 400 K the resistance of the samples became unstable preventing reliable noise measurements. The instabilities were probably caused by the dissolution of very small Si precipitates (<10 nm). This is important information because the dissolution will also take place during electromigration lifetime experiments.

High-resolution TEM of C60 thin films

1992 ◽  
Vol 50 (1) ◽  
pp. 108-109
Author(s):  
W. Krakow ◽  
N.M. Rivera ◽  
R.A. Roy ◽  
J.J. Cuomo
Keyword(s):  
Thin Films ◽  
High Resolution ◽  
Room Temperature ◽  
Bulk Material ◽  
Hexagonal Phase ◽  
Hexagonal Structure ◽  
Scanning Tunneling ◽  
Bravais Lattice ◽  
Face Centered Cubic ◽  
Tunneling Microscopy

The ability to fabricate buckminsterfullerenes, C60 molecules, in reasonably large quantities has made possible studies of the structural properties of this form of carbon when it is in a crystalline state. At room temperature, x-ray diffraction from three-dimensional bulk C60 crystals shows that the molecules are centered on sites of a face-centered-cubic Bravais lattice, A∘ = 14.2Å. Somewhat earlier in time, a study of C60/C70 bulk material using electron diffraction and high resolution electron microscopy has revealed a hexagonal phase. It is now believed that this phase is a simple cubic structure rather than a hexagonal structure. Since it is reasonable to expect that highly ordered C60 thin films will have superior properties to bulk material, several studies have been undertaken to understand the early stages of C60 thin film growth. Monolayer growth on GaAs has been studied by scanning tunneling microscopy., and on mica at room temperature using helium scattering. Along similar lines we have grown thin films of C60 molecules on mica and NaCl and characterized the crystallinity and local structural arrangements. Here we present some of our results of the electron microscope examination of these materials.

Comparison of Structural, Electrical and Thermoelectric Properties of Vacuum Evaporated SnTe Films of Varied Thickness

2020 ◽  
Vol 20 (6) ◽  
pp. 3879-3887
Author(s):  
Praveen Tanwar ◽  
A. K. Panwar ◽  
Sukhvir Singh ◽  
A. K. Srivastava
Keyword(s):  
Thin Films ◽  
High Resolution ◽  
Surface Morphology ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Electrical Measurements ◽  
Average Roughness ◽  
Thermoelectric Measurements ◽  
Tin Telluride ◽  
Te Material

As a key type of promising thermoelectric (TE) material p-type Tin Telluride (SnTe) vacuum evaporated thin films synthesized at room temperature (RT) on a glass substrate, report a significant enhancement in the figure of merit (ZT) value. The thicknesses of the nanostructured thin films were kept about 145 nm and 275 nm. High-resolution X-ray diffraction (HRXRD) outlines the polycrystalline nature in both thin films. Surface morphology of these films is composed of grains of variable sizes as elucidated by scanning electron microscopy (SEM). This observation is further confirmed by atomic force microscopy (AFM) wherein the average roughness, surface skewness, and surface kurtosis parameters are used to analyze the surface morphology. Local microstructural features and crystalline structure have been confirmed from High-resolution transmission electron microscope (HRTEM) and the selected area electron diffraction (SAED) pattern, respectively. Four probes method was used to determine electrical measurements which confirm that the thin films have semi-metallic nature. Thermoelectric measurements carried out on these films resulted that the figure of merit increases as the thickness of the film increases. The maximum ZT value of ˜1.02 is obtained at room temperature for the thin film of thickness 275 nm.

Low-frequency noise in RF-sputtered Pb-doped 2223 phase BiSrCaCuO thin films

1994 ◽  
Vol 72 (5-6) ◽  
pp. 270-273 ◽  
Author(s):  
I. Shih ◽  
A. L. Li ◽  
W. W. Lam ◽  
C. X. Qiu ◽  
L. Ngo Phong ◽  
...  
Keyword(s):  
Thin Films ◽  
Normal State ◽  
Room Temperature ◽  
Low Frequency ◽  
Thermal Fluctuation ◽  
Temperature Curve ◽  
Frequency Noise ◽  
Superconducting Thin Films ◽  
Current Dependence ◽  
Noise Measurements

Noise measurements were carried out on RF-sputtered Pb-doped 2223 phase BiSrCaCuO superconducting thin films. No definite relationship between noise and bias current was observed in the superconducting state, however, a square-current dependence of noise was found in the normal state. The magnitude of the noise in the BiSrCaCuO films at room temperature was one to five orders of magnitude larger than that in a normal metal. Near the tail of the resistance transition, noise peaks were observed that were 3–12 K below the maximum of the derivative resistance–temperature curve. Noise dependence on frequency shows an approximate 1/f relation in both normal and superconducting states. The origin of the noise in the normal state is believed to be due to thermal fluctuation or resistance fluctuation and the larger noise near zero TC is possibly caused by grain boundaries in the films.

a-Si:N:H prepared by reactive evaporation in ammonia vapour

1987 ◽  
Vol 65 (8) ◽  
pp. 1020-1022
Author(s):  
R. D. Audas ◽  
D. E. Brodie
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Activation Energies ◽  
High Activation ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Reactive Evaporation ◽  
Ammonia Vapour ◽  
Optical Bandgaps ◽  
P Type

The reactive evaporation of Si in an ammonia ambient has been used to produce a-Si:N:H thin films. These films are "intrinsic-like" with low room-temperature conductivities (<10−12 S∙cm−1), high activation energies (0.9 eV), and high optical bandgaps (1.9 eV). Films prepared in this manner have been doped using co-evaporation of antimony (n type) and indium (p type). The addition of 2 at.% indium or antimony results in an increase in the room-temperature conductivity by eight and six orders of magnitude respectively. The undoped and doped samples are photoconductive when illuminated with a quartz-halogen source.

Effects of Deposition Temperature and Thermal Treatment on the Structure of C60 and C70 Films

1994 ◽  
Vol 349 ◽  
Author(s):  
I. Rusakova ◽  
A. Hamed ◽  
P.H. Hor
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
High Resolution ◽  
Deposition Temperature ◽  
Room Temperature ◽  
Strong Dependence ◽  
Polycrystalline Thin Films ◽  
Mean Grain Size ◽  
High Resolution Tem ◽  
Solvent Residues

ABSTRACTC60 and C70 polycrystalline thin films, prepared by sublimation of powders onto carbon holey film substrates held at temperatures Ts of 40 and 200 °C, were investigated at room temperature using conventional and high resolution TEM. A strong dependence of grain size on Ts is observed. We obtain a mean grain size ˜25 nm for both C60 and C70 films when using Ts = 40 °C, but this size is ˜250 nm for C60 and ˜130 nm for C70 when using Ts = 200 °C. In all cases, however, an fc.c. structure with a high density of planar defecTs, twins and stacking faulTs, is observed. When a C60 film grown at Ts = 40 °C was annealed for several hours at only about 250 °C in vacuum, recrystallization took place, with grains as large as 250 nm now being present in the film. A condition to observe this recrystallization seems to be that the powder used to grow the film must be dried for long enough periods of time to minimize the amount of solvent residues.

A Liquid Nitrogen Cooled Stage for STEM

1974 ◽  
Vol 32 ◽  
pp. 444-445
Author(s):  
Louis T. Germinario
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Objective Lens ◽  
Thermal Drift ◽  
Specimen Holder ◽  
Resolution Capability ◽  
Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

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