Showing papers on "Evaporation (deposition) published in 1972"
TL;DR: In this paper, it was shown that continuous or intermittent ion bombardment during deposition can change the growth mode of thick deposits formed by sputtering or evaporation, and that this growth habit modification may also be obtained in sputter deposited nonmetallic materials and chemical vapor deposits by ion bombarding the deposit during growth.
Abstract: It is shown that continuous or intermittent ion bombardment during deposition can change the growth mode of thick deposits formed by sputtering or evaporation. The columnar morphology commonly found when deposits exceed 1 μ in thickness can be disrupted and the deposit densified by negatively biasing the deposit and subjecting it to ion bombardment during growth. This effect is found to occur in a number of metal systems and may be attributed to resputtering during growth. In the case of sputter deposited tantalum, the density of 6-μ thick films can be increased from 14 g/cm3 at 0 deposit bias to 16.3 g/cm3 at −500-V bias. The macroscopic stress in the deposited film is also shown to be a function of the deposit bias. It is proposed that this growth habit modification may also be obtained in sputter deposited nonmetallic materials and chemical vapor deposits by ion bombarding the deposit during growth.
150 citations
TL;DR: Low optical loss, in combination with the hotographic sensitivity of the KPR, offers the possibility of fabricating integrated optical circuits directly in the photoresist films.
Abstract: Light-guiding thin films of various materials have been deposited on glass substrates from liquid solutions by slow evaporation of the solvent. The attenuation of the guided light wave in some of these films is as low as that in the best films prepared by other methods. Film deposition from solution is done at or near room temperature. Therefore, this technique allows us to dope the thin films with organic molecules, e.g., laser dyes. The preparation and light-guiding properties of the doped and undoped films are described. The materials studied were epoxy, lead-silica, polyurethane, and Kodak photoresist KPR. Films of the first and second material have shown losses as low as 0.3 dB/cm at wavelengths of 0.633 microm and 1.064 microm, respectively. Films of polyurethane have been prepared with rhodamine 6G doping. When pumped with a pulsed nitrogen laser, the doped films showed optical gains of up to 100 dB/cm. The KPR films have an attenuation of ~1 dB/cm at 1.064 microm. This low optical loss, in combination with the hotographic sensitivity of the KPR, offers the possibility of fabricating integrated optical circuits directly in the photoresist films.
119 citations
TL;DR: In this article, a quasiequilibrium system has been developed to grow thick epitaxial films of PbS, PbTe and PbSe with tin on alkali halide substrates.
Abstract: During the past several years attempts have been made to grow thick epitaxial films of PbS, PbTe, PbSe, and their alloys with tin on alkali halide substrates. The thickest films which have been achieved using conventional evaporation techniques were limited to 10–15 μ m. We have developed a quasiequilibrium system which has yielded thick films of Pb1−xSnxTe ranging up to 328 μm. When combined with appropriate substrate preparations, this technique yields films having optical quality surfaces and good adherence to the substrate. In addition, the films may be easily removed from their substrates, intact and undistorted, by dissolving the substrates. Various electrical, optical, and thermal measurements on these thick films show that they are homogeneous. X-ray data indicate that the films are of high crystalline quality.
32 citations
Patent•
01 Jun 1972TL;DR: In this paper, a technique of reducing the susceptibility of aluminum semiconductor contacts to electromigration was proposed, where a small percentage of copper was formed on a semiconductor device by evaporation techniques, and the device was heated to a temperature of greater than 400 DEG to alloy the copper into the aluminum and quickly cooled to form copper rich precipitates between the grains of aluminum along the grain boundaries and triple points thereof.
Abstract: A technique of reducing the susceptibility of aluminum semiconductor contacts to electromigration. Aluminum contacts containing a small percentage of copper therein are formed on a semiconductor device by evaporation techniques. Subsequently the device is heated to a temperature of greater than 400 DEG to alloy the copper into the aluminum and quickly cooled to form copper rich precipitates between the grains of aluminum along the grain boundaries and triple points thereof for the purpose of reducing electromigration along grain boundaries.
27 citations
TL;DR: In this paper, the initial stages of adsorption and clustering are described, and the thermal accommodation coefficient was found to be between 0.8 and 1.0, which is the same as in this paper.
Abstract: The use of mass‐spectrometric molecular beam techniques allowed a detailed study to be made of the kinetics and thermodynamics of thin‐film deposition. Thermal accommodation, adsorption, nucleation, growth, and evaporation were measured for a single system. The deposits were characterized by their coverage‐dependent steady‐state evaporation rate, which is directly related to the thermodynamic potential of the evaporant in the film. The methods used and results obtained are exemplified by the present study of all stages of the ultrahigh‐vacuum (UHV) deposition of cadmium on the (100), (110), (111), (211), and (331) faces of germanium. In this paper, the initial stages of adsorption and clustering are described. The thermal accommodation coefficient was found to be between 0.8 and 1.0. On (111) substrates, adsorption of one monolayer of immobile cadmium atoms precedes nucleation of bulk cadmium. On the other substrates, 40% to 70% of a monolayer is adsorbed prior to nucleation. The extent of this adsorption...
27 citations
TL;DR: In this article, it is tentatively suggested that the spectrum showing the 1.4 eV edge is associated with another modification of lithium, which is not reconcilable with Ham's (1962) detailed band structure calculations.
Abstract: Lithium mirrors have been prepared by evaporation in ultra high vacuum onto cooled fused quartz and sapphire substrates; their optical properties were determined in situ by ellipsometry. Films deposited on sapphire show an absorption edge, uncorrected for possible broadening effects, at 2.4 eV at 125 K. The position of the edge is weakly temperature-dependent. The optical mass is 1.33. Lithium mirrors deposited on fused quartz have properties varying with time after deposition. Soon after evaporation the edge at 298 K appears at 1.4 eV and the optical masa is 1.7. The films then show variable properties but eventually assume a stable behaviour similar to that obtained with films deposited on sapphire. It is tentatively suggested that the spectrum showing the 1.4 eV edge is associated with another modification of lithium. The optical data for b.c.c. lithium are not reconcilable with Ham's (1962) detailed band structure calculations. If we assume that the proposed value for the energy gap at the N ...
27 citations
TL;DR: In this article, the optical properties of silicon oxide films with deposition conditions were measured, including the refractive index in the visible red, the U.V. absorption edge and the position of the infrared absorption band between 9 and 10 micro m.
24 citations
TL;DR: In this article, a correlation between surface structures of the chromium films and the environment in which they were grown could be made, and it was found in wet or dry environments that the stable Cr2O3 formed at all times and temperatures during the oxidizing process, and two forms of the nitride were observed.
Abstract: Reflection electron diffraction, electron microscopy, and ellipsometric techniques have been used to study the effect of various oxide and nitride treatments on the surface of chromium films. Thin films of chromium prepared by evaporation and deposited on glass substrates in 10−6-Torr vacuum were oxidized or nitrided for varying times at 50°C intervals in a 400°–600°C temperature range. In this study a correlation between surface structures of the films and the environment in which they were grown could be made. It was found in wet or dry environments that (1) the stable Cr2O3 formed at all times and temperatures during the oxidizing process, (2) two forms of the nitride were observed—the fcc CrN and the hexagonal βCr2N both always in combination with Cr2O3, (3) CrN was detected at a temperature of 450°C, (4) at temperatures above 450°C βCr2N was found and the CrN phase disappeared, (5) an increase in time at all temperatures resulted in grain growth of all compounds. Data obtained for varying conditions ...
22 citations
TL;DR: In this paper, the authors measured the thickness of the oxide layer by using the dispersion relation of surface plasmons, which was shown to be useful for studying thin oxide layers.
Abstract: The energy-loss spectra of 350-eV electrons reflected from aluminum were observed during the oxidation of a freshly evaporated film. The loss spectra due to surface plasma showed characteristic variations in the process of oxidation. The thickness of the oxide layer was measured by using the dispersion relation of surface plasmons. This method was shown to be useful for studying thin oxide layers (<20 A). Oxide films grew on aluminum in different ways when the pressures were 1×10−7 and 1×10−8 Torr, where most of the residual gas was hydrogen and water. In the former case, the oxide layer in the initial stage was islandlike, whereas in the latter case it was uniform. Oxide films grew abruptly about 20 min after evaporation of the aluminum, as was confirmed by an analysis of the residual gas. The rate of growth of uniform oxide layers was consistent with a logarithmic law.
22 citations
TL;DR: In this article, a study has been made of the deposition distributions of various evaporation sources and their geometries optimized for the specific purpose of fabricating accelerator targets from small quantities of isotopic materials.
18 citations
TL;DR: Amorphous thin films of antimony selenide of controlled composition have been prepared by vacuum evaporation and their influence on optical properties is discussed in this article, where the optical energy gap is shown to increase with increasing selenium content.
Abstract: Amorphous thin films of antimony selenide of controlled composition have been prepared by vacuum evaporation. Various evaporation techniques are compared and their influence on optical properties is discussed. The optical energy gap is shown to increase with increasing selenium content.
TL;DR: In this article, the dependence of the reflectance of Re and W on the substrate temperature during deposition, film thickness, and aging during exposure to air was discussed, indicating that the oxide films formed on both film materials at room temperature were very thin.
Abstract: Discussion of the dependence of the reflectance of Re and W on the substrate temperature during deposition, film thickness, and aging during exposure to air. Re and W of 99.99% purity were evaporated with a 6-kW fine-focused electron gun and deposited on glass and fused quartz plates of various temperatures ranging from 40 to 500 C. With Re, films of highest reflectance were obtained by evaporation onto unheated substrates, whereas with W, heating of the substrate greatly increased the reflectance of the deposited films. For both metals, the reflectance losses during extended exposure to air remained rather small, indicating that the oxide films formed on both film materials at room temperature were very thin.
TL;DR: In this article, the structural properties of epitaxial Si-Ge structures of abrupt junction, prepared by UHV evaporation, were investigated as a function of the condensation temperature, the thickness of the grown layer and the cooling rate.
TL;DR: In this paper, it was shown that the buildup of negative charge from stray electrons on insulating substrates apparently repels oxygen ions thus altering the stoichiometry of the final film.
Abstract: In previous experiments the authors explored the deposition of Al2O3 films on silicon by electron-beam evaporation. These films exhibited unstable offset voltages, measured by C–V techniques, and poor radiation resistance. This paper describes the continuation of this study, with the discovery that electrostatic charges developed on the substrates during the electron-beam deposition process play a significant role in affecting the electrical and physical film properties. These investigations indicate that the buildup of negative charge from stray electrons on insulating substrates apparently repels oxygen ions thus altering the stoichiometry of the final film. Control of this charge buildup alters both the electrical and optical properties of the Al2O3 films. Al2O3 films varying in shades of brown to completely clear are produced by altering the electrostatic fields from −22 V (for the darkest films) measured between substrate and ground to less than −2 V between substrate and ground (for the clearest fil...
TL;DR: In this article, the optical and magneto-optical properties of these films are studied to characterise them and the optical transitions in YbTe and YbSe are shown to arise from a diamagnetic ground state of Yb 2+ ion.
TL;DR: In this paper, single-crystal (111) Pb0.918Sn0.082Se films have been deposited on cleaved BaF2 substrates by both the flash and the one-boat evaporation methods.
Abstract: Single‐crystal (111) Pb0.918Sn0.082Se films have been deposited on cleaved (111) BaF2 substrates by both the flash and the one‐boat evaporation methods. On cleaved (111) CaF2 substrates, single‐crystal (111) films were obtained only when one‐boat evaporation was used. At 87°K, mobilities up to 1.3×104 cm2/V sec have been obtained.
TL;DR: In this paper, electrical resistance and optical transmission, reflexion and absorption of thin films of the alkali metal cesium were measured as a function of thickness, the latter for ∥ and ⊥ polarised monochromatic radiations having wavelengths between 3000 and 9000 A incident from the vacuum side as well as from the quartz support side at angles of 45 ° and ca 30 ° resp.
Abstract: Electrical resistance and optical transmission, reflexion and absorption of thin films of the alkali metal cesium were measured as a function of thickness, the latter for ∥ and ⊥ polarised monochromatic radiations having wavelengths between 3000 and 9000 A incident from the vacuum side as well as from the quartz-support side at angles of 45 ° and ca 30 ° resp. The films were prepared by evaporation in static ultra-high vacuum (∼10−10 Torr) onto a cooled (70 K) smooth surface of a thin, plane-parallel plate of polycrystalline quartz. The thickness of the slowly condensing films was varied continuously from zero to some thousand Angstrom-units corresponding to the bulk metal.
TL;DR: In this article, the fabrication of surface barrier charged particle detectors has been studied and it has been found that the best results are obtained when the gold evaporation is carried out in wet oxygen at pressures of the order to 5×10 −3 torr.
TL;DR: In this paper, optical transmission, reflexion and absorption of thin films of the alkali metal rubidium were measured as a function of thickness for polarised monochromatic radiations having wavelenghts between 3000 and 6000 A, incident from the vacuum side as well as from the quartz-support side at angles of 45 ° and 30 ° resp.
Abstract: Optical transmission, reflexion and absorption of thin films of the alkali metal rubidium were measured as a function of thickness for ∥ and ⊥ polarised monochromatic radiations having wavelenghts between 3000 and 6000 A, incident from the vacuum side as well as from the quartz-support side at angles of 45 ° and 30 ° resp. The films were prepared by evaporation in static ultrahigh vacuum (∼ 10−10 Torr) onto a cooled (90 °K) smooth surface of a thin, plane-parallel plate of polycrystalline quartz. The thickness of the slowly condensing films was varied continuously from zero to some thousand Angstrom-units corresponding to the bulk metal. The results obtained permit the identification of the volume- or the surface-character of the different plasma oscillations and, in the latter case, the surface they are attached to, the determination of their resonance frequency and a quantitative analysis of their developement with increasing film thickness.
Patent•
10 Jul 1972
TL;DR: A powdery mixture of cobalt hydroxide, aluminium oxide, and oxides which absorb substantially no visible light, preferably silicon dioxide, is vacuum evaporated in an oxidizing atmosphere and deposited on a base material and subsequently heat treating at approximately 300*C.
Abstract: A powdery mixture of cobalt hydroxide, aluminium oxide, and oxides which absorb substantially no visible light, preferably silicon dioxide, is vacuum evaporated in an oxidizing atmosphere and deposited on a base material and subsequently heat treating at approximately 300*C. The coating of the base material thereby obtained is a hard, well adherent, pure blue colored and transparent film. The proportions of the principal components of the primary mixture used for evaporation are 30 to 40 percent of cobalt hydroxide and 5 to 15 percent of aluminium oxide, the refractive index of the whole mixture is approximately equal to the refractive index of the base material and the thickness of the film produced is approximately 1/1000 mm.
TL;DR: In this paper, thin films of Au, Ag, Pt, Pd, In, Sn, Bi, and Te were vacuum vapor deposited onto air-cleaved NaCl (001) substrates in the absence of an electric field and in the presence of dc fields (in the plane of the substrate), ranging in intensity from 10 to 103 V/cm.
Abstract: Thin films of Au, Ag, Pt, Pd, In, Sn, Bi, and Te were vacuum vapor deposited onto air‐cleaved NaCl (001) substrates in the absence of an electric field and in the presence of dc fields (in the plane of the substrate), ranging in intensity from 10 to 103 V/cm. The vacuum environments were varied between 10−6 and 10−9 Torr, and evaporation rates ranged from 10 to 103 A/sec. Substrate temperatures were varied from 25 to 350°C for a distribution of mean film thicknesses ranging from 15 to 1200 A. No significant effects of an electric field applied in the plane of the substrate were observed upon examination and comparison of representative film samples by transmission and scanning electron microscopy.
TL;DR: The ideal standard for accurate nuclear measurements can be approximated in many cases by thin layers prepared by vacuum evaporation as mentioned in this paper, and the typical difficulties inherent in these methods with respect to realization and definition of the standard are reviewed in general.
TL;DR: In this paper, the resistivity of Cu, Cu + 100 ppm Fe and Cu + 200 ppm Fe films was measured as a function of temperature from 1 to 300 K. The results on films evaporated at room temperature are compared with contradicting data of other authors.
TL;DR: In this paper, the preparation of thin supported films of Ra, U, Np, Pu and Am isotopes has been studied using vacuum evaporation from electron-bombarded effusion cells.
TL;DR: In this paper, it was revealed that the structure and stability of the films were strongly affected by the quality of the vacuum during deposition, and that the films prepared in a vacuum of 2*10-4 Torr on the substrate at 20 degrees C exhibited an amorphous like halo pattern of electron diffraction but careful analysis revealed that they consisted of very fine grains having fcc structure.
Abstract: Iron films were made by evaporation in a technical vacuum on amorphous carbon substrates at 20 degrees C and 120 degrees C. The structure and stability of the films were strongly affected by the quality of the vacuum during deposition. The films prepared in a vacuum of 2*10-4 Torr (O2) on the substrate at 20 degrees C exhibited an amorphous like halo pattern of electron diffraction but careful analysis revealed that they consisted of very fine grains having fcc structure. Films prepared on the substrate at 120 degrees C in the same vacuum were a mixture of wustite and a small amount of amorphous like iron which transformed to the defective magnetite structure by exposure to the air for a short period.
TL;DR: In this paper, the structure and epitaxy of silicon films were found to be markedly influenced by the purity of the Si source, ambient pressure during evaporation, substrate surface condition, deposition rate, and substrate temperature.
Abstract: Silicon films, 30–300 A in thickness, evaporated (using an electron beam evaporation technique) onto NaCl substrates cleaved in ultrahigh vacuum and held at 25–500 °C at various deposition rates (0.1–8 A/sec) have been investigated by reflection electron diffraction and transmission electron microscopy. It was found that the structure and epitaxy of films were markedly influenced by the purity of the Si source, ambient pressure during evaporation, substrate surface condition, deposition rate, and substrate temperature. Decoration of imperfections of the substrate surface was obtained with Si deposited at relatively slow rate (0.1–0.3 A/sec). Films produced on the substrates at 25–300 °C were amorphous. The amorphous to crystalline transition temperature was in the range of 300–400 °C. Epitaxial orientation of films (001)Si‖(001)NaCl with [100]Si‖ [100]NaCl was observed on the substrates at 400 °C at the slow deposition rate. The epitaxial films included microtwins with the twinning planes of {111}. The gr...
Patent•
01 Dec 1972
TL;DR: Cross-linking polymers as mentioned in this paper are polyethylene, polypropylene, P.T.F.E., polytetrafluoropropylene, nylon or polycarbonates.
Abstract: 1298453 Cross-linking polymers NATIONAL RESEARCH DEVELOPMENT CORP 31 Dec 1969 [2 Jan 1969] 393/69 Heading C3P [Also in Division C7] A polymer is evaporated and deposited on a cooled substrate, and during deposition it is irradiated with, e.g. ultra-violet light to cause cross-linking of the polymer. The polymer may be polyethylene, polypropylene, P.T.F.E., polytetrafluoropropylene, nylon or polycarbonates. The irradiation may be continued after deposition.
TL;DR: In this article, a single crystal was grown from thin films produced by vacuum evaporation and condensation of polyethylene, and the single crystals were grown by subsequent heat treatment of the films in xylene.
Abstract: From thin films produced by vacuum evaporation and condensation of polyethylene, single crystals were grown by subsequent heat treatment of the films in xylene. Extended molecular chains composing the crystals are approximately 150 A in length, i.e., about 1.5 times the thickness of the crystal layers. Electron microscopic examination of the crystals revealed that they were morphologically similar to ordinary polyethylene and paraffin single-crystals, e.g., they sometimes exhibited a hollow pyramidal shape or typical spiral growth.
TL;DR: In this article, a tantalum carbide (TaC) film is formed on substrates by electron beam evaporation technique, where the range of substrate temperature is from 25°C to 1030°C.
Abstract: Films of tantalum carbide (TaC) known as a material with high melting point (3877°C) are formed on substrates by electron beam evaporation technique. The substrates are CaF2, MgO and NaCl single crystals cleaved in air. The range of substrate temperature is from 25°C to 1030°C. Pressures in the evaporation chamber are about 10-6 Torr during the deposition. Rates of deposition are about 25 A per second. Thicknesses of the deposits are less than 500 A. These films are investigated by transmission electron diffraction and electron microscopy. Diffraction patterns of TaC films deposited on CaF2 (111) and NaCl (100) surface are (111) and (100) spots with Debye-rings, respectively. Perfect epitaxial growth is observed for the TaC film deposited on the MgO (100) surface. The orientation relations are TaC(100)//MgO(100) and TaC[001]//MgO[011] at substrate temperatures above 390°C, and below this temperature Debye-rings are observed.