摘要:

By adding excess niobium to the molten metal pool of a rod-fed evaporation source in order to approximate a steady state condition, reproducible transfer of source material containing niobium, titanium, chromium, and aluminum has been achieved. Single source evaporative coating of this material has not been considered practical prior to this work because of the factor of106difference in vapor pressure between the most volatile element and the least volatile element. As produced, the coatings had a banded structure. A heat treatment homogenized the coatings. A model is suggested to explain the banded structure.

ISSN:0022-5355    

DOI:10.1116/1.1318051

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The formation of thin Au films by vacuum evaporation on lead and tin chalcogenides is investigated. Single crystal chalcogenide substrates are prepared by vacuum evaporation onto KCl. The films are studied by RHEED prior to removal from the KCl substrate and by TEM and TED after removing the composite Au–chalcogenide film from the KCl. A remarkable variety of orientations and particle shapes is observed. The saturation particle density varies over a very wide range as a function of substrate material and temperature. Results are discussed and compared with the growth of Au on alkali halides.

ISSN:0022-5355    

DOI:10.1116/1.1318052

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Copper was ion plated onto a steel substrate to form a highly adherent surface coating. Electron probe examination of the copper/steel interfacial region showed that the ion-plated copper had penetrated the steel substrate to a depth of about 7–8 μ to form a graded, diffuse interface. The excellent adhesion of the coating to the substrate, which was examined by a 90° bend test and the standard Scotch Tape Test, can be attributed to the diffused interface formed by ion plating.

ISSN:0022-5355    

DOI:10.1116/1.1318053

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The mean value of density for six samples of a siloxane manometer fluid is1.06311 g/cm3with an estimated standard deviation of11×10−5 g/cm3for the lot-to-lot variation in density of this fluid. From this result it is concluded that for use of this material in manometry to the 0.01% level the density of the actual fluid used must be determined.

ISSN:0022-5355    

DOI:10.1116/1.1318054

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The modulation characteristics of a Bayard–Alpert gauge have been investigated in the presence of a large residual current of desorbed ions, following exposure of the gauge to oxygen. Having observed an increase in the collector current on modulation, when the gas phase ion current was relatively small, modulation factors were measured for the desorbed ion current and were found to vary in magnitude up to 0.2. A sharp peak, which increased the amplitude of the mean residual current by approximately 30%, was also found in the modulation curve betweenVmg=−10and −35 V. Computed potential distributions and ion trajectories have shown that this peak can be attributed to the focussing action of the electrostatic field on energetic ions desorbed from the modulator. Experimental verification of this hypothesis was obtained by selective cleaning of the grid and modulator using electron bombardment. The presence of such a peak would produce errors in the proposed alternative modes of modulation in which a modulator-to-grid potential of −20 V is used.

ISSN:0022-5355    

DOI:10.1116/1.1318055

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The initial stages of the deposition of thin zinc films on the (110) and (100) surfaces of germanium single crystals have been studied. A mass-spectrometric molecular beam method was used in ultrahigh vacuum. The evaporation rate of the thin film was measured during depositions at various temperatures and beam intensities. On both substrates, the adcoverage approaches complete saturation of available adsorption sites before nucleation of bulk zinc starts. Nucleation therefore occurs on a composite substrate. On (110) substrates, the critical nucleation stage of thin film formation is determined by the coverage only. The thermodynamic parameters of the critical deposit, such as the equilibrium evaporation rate, the thermodynamic potential, and the differential binding energy, have been determined. These thermodynamic parameters determine the critical beam intensity necessary for nucleation. The deposition of zinc on (100) substrates is more complex. The critical nucleation state of the deposit is determined not solely by the coverage, but also by the deposition conditions of temperature and beam intensity. In such a case, thermodynamic parameters cannot be obtained by the present technique.

ISSN:0022-5355    

DOI:10.1116/1.1318056

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

This paper describes a study of the outgassing from the pinch-off of copper tubulations. The gas released is approximately 99.5%CO2and 0.5%O2. The amount of gas varies with the type of copper, its diameter, and the treatment given to the tubulation prior to the pinch-off. The amount of gas can vary from1×10−6 cm3(STP) for 0.250 in. o.d., 0.182 in. i.d. OFHC tubulations that have not been cleaned or baked, to3×10−9 cm3(STP) for the same tubes that have been chemically cleaned, and then baked on the vacuum system. Refrigeration tubing showed the same initial amount of outgassing, but still outgassed3×10−8 cm(STP) even after cleaning. With careful treatment,0.125 in. o.d.×0.080 in. i.d.OFHC tubulations release less than3×10−10 cm3(STP) of theCO2–O2mixture during a pinch-off.

ISSN:0022-5355    

DOI:10.1116/1.1318057

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

An investigation of the standard surface cleaning techniques, e.g., oxygen reaction at high temperatures and argon ion bombardment, has been carded out with special reference to Ni(111), Ni(100), and Ni sheet using Auger electron spectroscopy (AES) to monitor surface conditions. Carbon, sulphur, chlorine, nitrogen, and oxygen are observed as impurities on these surfaces. On Ni(111) a heavy carbon deposit (>10 Å thick) is noted. Argon ion bombardment is not effective in removing this layer. High temperature reaction (>700°C) with oxygen is required to eliminate the surface carbon. The kinetics of this reaction are recorded by monitoring the rate of production of carbon monoxidedNCO/dtwhich obeys the relationshipdNCO/dt=kPO20.9±0.1 exp−(32±2 kcal mol−1)/RTin the temperature range 663–917°C and oxygen pressure range1.0×10−8to5.9×10−7 Torr. After this carbon removal the sulphur and chlorine impurities are eliminated using argon ion bombardment. Reaction with oxygen at 1100°C and10−6 Torris also effective in removing these latter impurities. At this point only a small carbon peak due to slow diffusion from the bulk is present on the surface. However, a short anneal to 700 °C for<1 min caused small amounts of sulphur and chlorine to reappear. This effect is discussed in terms of diffusion and support effects. The minimum attainable coverage(θs)of sulphur on the Ni(111) wasθs=0.1. For Ni(100) and Ni sheet a much smaller carbon peak compared to Ni(111) is observed. This may be “removed” by heating alone. Some reaction of surface carbon and oxygen takes place to give gaseous carbon monoxide. Some carbon diffuses into the bulk. On cooling, carbon slowly diffuses to the surface. Sulphur and chlorine impurities may be removed by argon ion bombardment. Removal of these impurities by oxygen reaction at high temperatures is unsatisfactory. Oxidation occurs. Hydrogen reduction is not particularly successful, although this oxygen can be removed by prolonged argon ion bombardment.

ISSN:0022-5355    

DOI:10.1116/1.1318058

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Thin film sandwiches of Cr–Cu and Cr–Cu–Cr are widely used for a number of electronic applications, but there has been no report of any systematic investigation of interactions or stability in these films. We have studied diffusion, oxidation, and stability in these films using resistometric techniques and electron diffraction and have found that these systems are useful only at low temperature (<175°C) in oxidizing environments. At high temperatures in any environment, oxidation and diffusion result in many problems: resistivity instabilities, oxidation, hardening (bonding problems), variable solderability, and extreme difficulty in dielectric overcoating. Techniques are discussed to circumvent some of these problems.

ISSN:0022-5355    

DOI:10.1116/1.1318059

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The phenomena of ion trapping in electron beams are studied experimentally. For a tubular electron beam the total trapped ion charge equals that of the electron charge if no opening of the trap occurs by any negative potential electrode. When a second electron beam is introduced along the axis of the tubular beam, very high ion densities can be established, because the slow electrons created by ionizing collisions of the axial electron beam can neutralize the ionic charge on the axis.

ISSN:0022-5355    

DOI:10.1116/1.1318060

出版商:American Vacuum Society    

年代:1973

数据来源: AIP