CONDENSATION COEFFICIENTS OF SILVER, GOLD, AND COPPER IN VACUUM DEPOSITION

1958 ◽  
Vol 36 (9) ◽  
pp. 1148-1153 ◽  
Author(s):  
S. Chandra ◽  
G. D. Scott

A beam of atoms striking a substrate will in general not condense completely, but some of the incident atoms will re-evaporate. The condensation coefficient– denfined as the ratio of the number of atoms condensing to the total number incident on the substrate–has been determined for silver at substrate temperatures from −30 °C to 170 °C, and for gold and copper at temperatures from 25 °C to 165 °C. For silver at room temperature the condensation coefficient is found to be 0.936, which indicates 6.4% of the incident atoms are re-evaporated or diffusely reflected. By a simple graphical analysis of the results it is shown that the temperature below which complete condensation occurs is 200 °K for silver, 230 °K for gold, and 180 °K for copper.

Author(s):  
M. Shiojiri ◽  
Y. Saito ◽  
M. Sato

Crystals of Te prepared by vacuum-deposition on cleaved NaCl surfaces at temperatures ranging from 20 to 140°C have been studied by SEM and TEM observations. The deposition was done at a deposition rate of 0.3 nm/s, monitored with quartz crystal oscillating microbalance. After the deposited films were backed by carbon films, they were wet-stripped from the substrates and mounted on standard electron microscope grids.Figure 1 shows electron micrographs of the films in different thicknesses which were prepared at different substrate temperatures. At the initial stage of deposition, spherical or polyhedral crystallites with the hexagonal structure grew with random orientations on the substrates. On the substrate at room temperature, the crystallites became large keeping the same shape and the number of the crystallites increased, as the film thickness increased. On the substrates above 80°C, they grew into slender crystals elongating along the c-axes, with increasing film thickness. The number of crystals did not increased so much.


Author(s):  
T.E. Pratt ◽  
R.W. Vook

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.


1993 ◽  
Vol 313 ◽  
Author(s):  
Mary Beth Stearns ◽  
Yuanda Cheng

ABSTRACTSeveral series of CoxAg1-x granular thin films (-3000Å) were fabricated by coevapora-tion of Co and Ag in a dual e-beam UHV deposition system at varying substrate temperatures. These films have low field magnetoresistance values as large as 31% at room temperature and 65% at liquid N2 temperature. The structure of the films was determined using magnetization measurements as well as x-ray and various electron microscopy techniques. The composition was determined using Rutherford backscattering spectroscopy. The Magnetoresistance was measured at both room and liquid N2 temperatures.We deduce from the magnetization and RBS Measurements that the films consist of Co globules embedded in a Ag Matrix and that there is no appreciable mixing of the Co and Ag atoms in the films deposited at substrate temperatures ≥ 400°K. The size of the Co globules is seen to increase with increasing Co concentration and the maximum magnetoresistance occurs in those films having the smallest Ag thickness which provides magnetic isolation of the Co globules.We suggest that the large magnetoresistance of these films arises from the same mechanism which causes the low field magnetoresistance in pure ferromagnets, namely, the scattering of the highly polarized d conduction electrons of the Co at magnetic boundaries. The large increase in the room temperature magnetoresistance of the CO/Ag films as compared to those of pure 3d ferromagnetic films is due to the distance between the magnetic boundaries being reduced to a few nanometers, because of the small size of the single domain Co globules, as compared to a few microns in 3d ferromagnets.


Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.


1981 ◽  
Vol 4 ◽  
Author(s):  
P. S. Peercy ◽  
D. M. Follstaedt ◽  
S. T. Picraux ◽  
W. R. Wampler

ABSTRACTLattice defects and precipitates induced in unimplanted and Sb-implanted <110> single crystal Al by single pulse irradiation with a Q-switched ruby laser were studied using ion beam analysis and electron microscopy. The absorbed laser energy during irradiation is directly measured in these studies to allow precise numerical modeling of the melt times and temperature profiles. For unimplanted Al, slip deformation gives rise to increased channeled yields throughout the analyzed depth and occurs for energies well below the melt threshold energy of 3.5 J/cm2. Slip deformation is also observed for irradiation energies above the melt threshold energy, and melting is accompanied by a discontinuous increase in the minimum channeling yield, X min- Implanted Sb (to ∼2 at.% peak concentrations) is found to impede epitaxial regrowth and result in polycrystalline Al formation for laser energies such that the melt front is believed not to penetrate through the Sb-containing region. For deeper melt depths, a metastable alloy is formed with up to 35% of the Sb located in substitutional sites. AlSb precipitate formation in the melt was not observed for room temperature irradiations; however, randomly oriented AlSb precipitates are observed for irradiation at substrate temperatures of 100 and 200 °C These measurements yield an estimated time for nucleation of AlSb precipitates in molten Al of 5 nsec < tnuc < 25 nsec.


2004 ◽  
Vol 818 ◽  
Author(s):  
Wei Chen ◽  
Kian Ping Loh ◽  
Hai Xu ◽  
A.T.S. Wee

AbstractA honeycomb-like SiC reconstructed surface with regular, periodic porosity in the nano-scale range has been used as an effective template for the formation of monodispersed Co nanoclusters. In-situ scanning tunneling microscopy (STM) was used to study the nucleation process of the Co nanoclusters on this template. The deposition of Co at different substrate temperature was investigated by STM. It is found that the failure in the deposition of Co nanoclusters on the SiC honeycomb template with substrate temperatures higher than room temperature (RT) might be due to the high desorption rate of the adsorbed Co atoms.


1983 ◽  
Vol 27 ◽  
Author(s):  
H.W. Alberts

ABSTRACTProton and α-particle channeling were used to study the radiation damage caused by the implantation of 160 keV Mg ions in InSb. The implantations took place at various substrate temperatures ranging from room temperature to temperatures just below the melting point and doses ranging from 5.1013 to 1.1016 Mg+ cm−2. The isochronal annealing of the room temperature implanted crystals started at 200°C and damage could not be completely removed even at temperatures just below the melting point. For crystals implanted at elevated substrate temperatures no annealing effects during implantation occured up to 400°C. Above 400°C a sharp reduction of damage indicates that the rate of formation of more complex defect configurations during the implantation process becomes smaller than the annihilation rate of the vacancy-interstitial pairs. A non-linear dependence exists between the degree of radiation damage in the InSb lattice and the implanted dose.


1994 ◽  
Vol 356 ◽  
Author(s):  
D. D. Knorr ◽  
K.P. Rodbell

AbstractBlanket films (1 μm thick) of both A1-0.5Cu and A1-0.15Pd were deposited at room temperature, 150°C, and 300°C. Stress in the as-deposited wafers increased with substrate temperature, as expected from the thermal expansion mismatch on cooling. All conditions were tiicrmally cycled to 450°C three times while continuously monitoring stress. The shapes of the curves were different for the two alloys because precipitates dissolve and reprecipitate in AlCu, but are present over the entire temperature range in AlPd. Lesser differences were evident comparing the stress-temperature behavior for the various substrate temperatures within a single alloy. The precipitate structure also influences the grain growth during thermal cycling, where substantially larger median grain sizes are found in AlCu compared to AlPd.


2013 ◽  
Vol 749 ◽  
pp. 643-647 ◽  
Author(s):  
Lei Li ◽  
Ya Feng Lu ◽  
Wen Xue Li ◽  
Li Ying Zeng ◽  
Yi Yang ◽  
...  

Ti-6Al-4V films were deposited by direct-current magnetron sputtering at different substrate temperatures. The structure and the surface morphology of the films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The hardness and elastic moduli of Ti-6Al-4V films were measured by nanoindentation test. The results showed that the phase direction of the films deposited at room temperature was (102) orientation, and turned to almost complete (002) preferred orientation at 300°C. For a higher temperature of 500°C, the preferred orientation of the film disappeared and presented a random grain orientation. The hardness and elastic moduli of Ti-6Al-4V films obviously showed the dependence on the temperature. The relationships among temperature, microstructure and mechanical properties of Ti-6Al-4V films were discussed in this paper.


2016 ◽  
Vol 439 ◽  
pp. 54-59 ◽  
Author(s):  
Ku-Yen Lin ◽  
Yan-Jun Wang ◽  
Ko-Lun Chen ◽  
Chun-Chuen Yang ◽  
Ching-Yuan Ho ◽  
...  

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