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Nov 1980

Volume 17, Issue 6, pp. 1287-1386


Transition metal compound surfaces I: The cubic sodium tungsten bronze (NaxWO3) surface

M. A. Langell and S. L. Bernasek

J. Vac. Sci. Technol. 17, 1287 (1980); http://dx.doi.org/10.1116/1.570657 (9 pages) | Cited 2 times

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The two dimensional surface structure and the surface chemical composition of (100) cubic sodium tungsten bronze (NaxWO3) has been investigated using low energy electron diffraction and Auger electron spectroscopy. Single crystals with bulk x values ranging from 0.5 to 0.9 were examined. The (100) surface exhibits the square symmetry of the WO3 lattice, with fractional order features corresponding to ordered sodium row structures which depend on the crystal x value. Auger spectra support covalent bonding models of these materials, in which sodium contributes little to the lattice binding. LEED and Auger results indicate sodium depletion in the surface region. In addition, evidence of a sodium order/disorder transition in the surface region is obtained.
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68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
61.72.jd Vacancies
61.72.jj Interstitials

Transition metal compound surfaces II: The tungsten trioxide single crystal surface

M. A. Langell and S. L. Bernasek

J. Vac. Sci. Technol. 17, 1296 (1980); http://dx.doi.org/10.1116/1.570658 (7 pages) | Cited 3 times

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The surface properties of macroscopic single crystals of tungsten trioxide have been investigated using low energy electron diffraction and Auger electron spectroscopy. The stoichiometric (100) surface shows evidence of distortion to triclinic symmetry, indicated by a doubled feature diffraction pattern. A WO3 crystal surface grown several degrees away from the (100) plane exhibits a diffraction pattern which may be understood in terms of the formation of a [103] shear plane in the nonstoichiometric surface region. This surface is discussed in relation to the mechanism of oxidation of tungsten. Auger spectra provide support for a covalent bonding network in the WO3 surface region, similar to that observed for sodium tungsten bronzes.
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68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
61.72.jd Vacancies
61.72.jj Interstitials

The Si(111)–Pd interface: Spectroscopic evidence of chemical processes at liquid nitrogen temperature

I. Abbati, L. Braicovich, B. De Michelis, and U. del Pennino

J. Vac. Sci. Technol. 17, 1303 (1980); http://dx.doi.org/10.1116/1.570659 (3 pages) | Cited 1 time

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We present the results of angle integrated photoelectron spectroscopy (hν=21.2 eV) on Si(111)–Pd interfaces. We have found that some intermixing between Si and Pd takes place also when the interface is prepared at liquid nitrogen temperature (LNT). After preparation at LNT the intermixing increases at room temperature (RT). The results are discussed in connection with the interface formation mechanism.
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79.60.Jv Interfaces; heterostructures; nanostructures
73.40.Ns Metal-nonmetal contacts

Phosphorus concentration in hydrogenated amorphous silicon using ion‐implanted references

J. H. Thomas

J. Vac. Sci. Technol. 17, 1306 (1980); http://dx.doi.org/10.1116/1.570660 (3 pages) | Cited 4 times

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The phosphorus content in glow‐discharge deposited hydrogenated‐amorphous silicon film has been determined using Auger electron spectroscopy. Precision low concentration phosphorus ion‐implants into hydrogenated amorphous silicon were used as standards to accurately determine the sensitivity factor for phosphorus in hydrogenated amorphous silicon.
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79.20.-m Impact phenomena (including electron spectra and sputtering)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
61.72.U- Doping and impurity implantation

X‐ray photoelectron spectroscopy study of the surface adsorption of lead naphthenate

P. A. Bertrand and P. D. Fleischauer

J. Vac. Sci. Technol. 17, 1309 (1980); http://dx.doi.org/10.1116/1.570661 (6 pages)

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The adsorption of lead naphthenate on the surfaces of metals, oxides, and sulfides was studied by means of x‐ray photoelectron spectroscopy (XPS). Lead naphthenate physically adsorbs on all surfaces. It chemisorbs on surfaces with basic sites, such as oxides, sulfides, and metals treated in basic solutions before adsorption. The two states have distinct XPS spectra: the Pb(4f7/2) binding energy for the physically adsorbed state is 139.1 eV, whereas that for the chemisorbed state is 136.6 eV. Conditions of surface preparation that result in the formation of each state are described.
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68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)

AES study of tin–lead alloys: Effects of ion sputtering and oxidation on surface composition and structure

R. P. Frankenthal and D. J. Siconolfi

J. Vac. Sci. Technol. 17, 1315 (1980); http://dx.doi.org/10.1116/1.570662 (5 pages) | Cited 3 times

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Using Auger electron spectroscopy, we have investigated the surface composition of a 60:40 soft solder (72a/oSn−28a/oPb), the effect of ion sputtering on the composition and structure of the surface, and the composition of the oxide film that forms during ambient and low pressure oxidation. The alloy surface is, on the average, enriched in lead. The lead‐rich phase is preferentially sputtered during ion etching. Tin in the alloy surface oxidizes preferentially; however, if the conditions are such that the alloy surface layer becomes depleted in tin, lead will be oxidized.
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82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
79.20.-m Impact phenomena (including electron spectra and sputtering)
81.05.Bx Metals, semimetals, and alloys

Surface texturing of copper by sputter etching with applications for solar selective absorbing surfaces

P. M. Curmi and G. L. Harding

J. Vac. Sci. Technol. 17, 1320 (1980); http://dx.doi.org/10.1116/1.570663 (6 pages) | Cited 5 times

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Solar selective absorbing surfaces have been produced by texturing copper specimens in a novel magnetron cosputtering system which allows high rate sputter etching of a moving metal plate seeded with low sputter rate material. Unusual topographical features have been produced on copper in this apparatus using titanium seed. The variation of optical properties and surface morphology of the copper as a function of sputter etching conditions has been studied. Typical selective surfaces produced have absorptances α∠0.90 and emittances ϵ∠0.10 at 300 K.
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84.60.-h Direct energy conversion and storage
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
79.20.-m Impact phenomena (including electron spectra and sputtering)

Copper distribution in sputtered Al/Cu films

D. R. Denison and L. D. Hartsough

J. Vac. Sci. Technol. 17, 1326 (1980); http://dx.doi.org/10.1116/1.570664 (6 pages) | Cited 2 times

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The copper distribution in sputtered aluminum–copper films depends on copper concentration and deposition temperature. At high deposition rates the film temperature is high enough for diffusion to occur without external substrate heating. Targets containing 0.5%, 2%, and 4% copper were used to deposit films by dc magnetron sputtering. No segregation was found in the 0.5% Cu films at film deposition temperatures as high as 460°C. The 2% and 4% Cu films showed segregation, with the peak in the copper content located nearer the film–substrate interface. Auger and SEM data indicate that theta phase particles may form in this region during high rate deposition. These particles apparently redissolve slowly during 500°C postdeposition anneal. In contrast, 4% Cu films deposited by evaporation from a single source showed a similar as‐deposited profile, but a more rapid redistribution of the Cu during anneal. The sputtered films are reported to be more resistant to hillock growth and corrosion than the evaporated films. At rates above 10 kÅ/min, and under conditions where film temperature rose toward a steady‐state value, film melting or copper‐rich whiskers up to several microns in length were observed on the 4% Cu alloy.
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68.55.-a Thin film structure and morphology
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
68.60.-p Physical properties of thin films, nonelectronic
81.15.Cd Deposition by sputtering

Emission spectroscopy of glow‐discharge and sputtering plasmas used in amorphous Si:H film deposition

M. A. Paesler, T. Okumura, and W. Paul

J. Vac. Sci. Technol. 17, 1332 (1980); http://dx.doi.org/10.1116/1.570665 (4 pages) | Cited 5 times

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We analyze the optical emission spectra of glow discharge (g.d.) plasmas and find evidence for Si–H complexes. From a similar analysis of sputtering plasmas, we find that a significant silicon–hydrogen gas phase reaction does not occur. The dissimilarities of the plasmas out of which g.d. and sputtered films are condensed coupled with the similarities of the films themselves, lead us to reason that the properties of amorphous Si:H films are determined by structure that is locked into the growing film surfaces. To study the physics of how the hydrogen enters the Si:H matrix, one must turn to investigations of these surfaces.
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68.55.-a Thin film structure and morphology
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.80.Hc Glow; corona

Operation modes and its optical measurements of plasma stream transport system

T. Tsuchimoto

J. Vac. Sci. Technol. 17, 1336 (1980); http://dx.doi.org/10.1116/1.570666 (5 pages)

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The plasma stream transport method is a method where material transport is caused to occur in a plasma stream contained in a magnetic flux pipe. As the plasma stream contains only ions and electrons, the optical emission spectral lines from the plasma stream are considered to be representative of the material constituents of the plasma stream. A prototype plasma stream transport system was constructed and operated in three configurations or modes. The emission pattern was observed to depend on the operating mode and the measuring position along the plasma stream. Transport rates were estimated for the three operating modes and evaluated in terms of the optical emission measurements. The spectral lines at the vicinity of the substrate were found to correspond to the constituent of the deposition film.
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52.75.-d Plasma devices
52.30.-q Plasma dynamics and flow
52.25.Fi Transport properties
52.25.Os Emission, absorption, and scattering of electromagnetic radiation

Etching and film formation in CF3Br plasmas: some qualitative observations and their general implications

D. L. Flamm, P. L. Cowan, and J. A. Golovchenko

J. Vac. Sci. Technol. 17, 1341 (1980); http://dx.doi.org/10.1116/1.570667 (7 pages) | Cited 17 times

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CF3Br plasma discharges exhibit a number of unusual phenomena. Under some conditions silicon and SiO2 can be concurrently etched, while in other circumstances only SiO2 is etched and silicon is coated with a uniform, cross‐linked fluorocarbon film. Single crystal n‐doped silicon is etched more rapidly than undoped silicon. The fluorocarbon polymer overlays a monolayer of bromine at the silicon interface, but negligible bromine is incorporated into the fluorocarbon. Some chemical mechanisms which account for these observations are presented.
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52.40.Hf Plasma-material interactions; boundary layer effects
82.30.Cf Atom and radical reactions; chain reactions; molecule-molecule reactions
52.80.Pi High-frequency and RF discharges
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Gas plasma etching of ion implanted chromium films

T. Yamazaki, Y. Suzuki, and H. Nakata

J. Vac. Sci. Technol. 17, 1348 (1980); http://dx.doi.org/10.1116/1.570668 (3 pages) | Cited 3 times

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The etching characteristics of ion implanted chromium films in gas plasmas have been studied. It was found that in the case of Sb+ and As+ the etching rate of implanted chromium films decreased with increasing ion dose. It was also found that the etching rate depends on the surface impurity concentration, not on the total implanted dose of ions in the film. Using chromium film samples implanted with 20 keV ions at a dose of 1×1016 cm−2, reversely etched LSI photomask patterns have been obtained with good edge profiles. It is speculated that oxides of impurities are responsible for the reversal gas plasma etching.
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81.05.Bx Metals, semimetals, and alloys
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients
52.80.Hc Glow; corona

Plasma etching characteristics of chromium film and its novel etching mode

H. Nakata, K. Nishioka, and H. Abe

J. Vac. Sci. Technol. 17, 1351 (1980); http://dx.doi.org/10.1116/1.570669 (7 pages) | Cited 11 times

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The influences of chromium and chromium oxide films and gas compositions on plasma etching characteristics were investigated. Oxygen as well as chlorine is found to be responsible for etching. One possible etching reaction is proposed, in which a basic reaction product is assumed to be CrO2Cl2 which will be volatile in gas plasma. The impurities such as W, Fe, and Cu contained in the film become nonvolatile compounds which accumulate on the surface of the film and form a masking layer resulting in a suppression of the reaction. Anomalous etching modes called the contour and reverse etches were found with the chromium oxide films containing tungsten impurities. The mechanism of these anomalous etching modes is discussed, in which the accumulation of the tungsten compounds on the surface of the film is a basic mechanism. The reverse etch mode was applied to the fabrication of photomasks for MOS LSI.
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52.40.Hf Plasma-material interactions; boundary layer effects
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
81.05.Bx Metals, semimetals, and alloys

Ambient effects on the out‐diffusion of GaAs through thin gold films

C.‐A. Chang and N. J. Chou

J. Vac. Sci. Technol. 17, 1358 (1980); http://dx.doi.org/10.1116/1.570670 (2 pages) | Cited 11 times

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We have studied the ambient effects on the out‐diffusion of GaAs through thin gold films. Auger spectroscopic measurement shows accumulation of both Ga and As on the gold surface upon annealing in N2. The accumulation, however, is reduced in the presence of CO. This suppressed out‐diffusion by CO is in agreement with the surface potential model recently proposed.
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66.30.Ny Chemical interdiffusion; diffusion barriers
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors

Construction and performance characteristics of a low cost energy prefilter

J. H. Craig and J. L. Hock

J. Vac. Sci. Technol. 17, 1360 (1980); http://dx.doi.org/10.1116/1.570671 (4 pages) | Cited 6 times

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Construction and performance details are presented for a low‐cost energy filter (Bessel Box). Comparison is made between two devices of different lengths. The energy resolution of the longer device is shown to be 0.5 eV at a pass energy of 6 eV.
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07.75.+h Mass spectrometers

Energy‐selective SESD imaging utilizing a CMA

L. A. Larson, F. Soria, and H. Poppa

J. Vac. Sci. Technol. 17, 1364 (1980); http://dx.doi.org/10.1116/1.570672 (3 pages)

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A particularly simple conversion of a scanning Auger system for ESD ion energy distributions and scanning ESD has been developed. This approach combines the advantages of the small spot‐size electron guns and mapping systems developed for SAM with the capability of ESD for the detection of hydrogen. Our intended use for the device is detection and mapping of surface concentrations of hydrogen on metals. The characteristics of SESD are illustrated with the preliminary results of an investigation into the ESD properties of hydrogenic adsorbates on Nb. It is shown that the ESDIED exhibit distinct differences indicative of the surface preparation, and that the ESD ion angular distributions have an effect on the observed contrast relationships in SESD.
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79.20.Kz Other electron-impact emission phenomena

Single crystal LaB6 electron gun for variably shaped electron beam optics

M. Nakasuji and H. Wada

J. Vac. Sci. Technol. 17, 1367 (1980); http://dx.doi.org/10.1116/1.570673 (6 pages) | Cited 6 times

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A single crystal LaB6 electron gun for variably shaped beams was developed. For the 50 A/cm2 density, 3 μm length maximum beam size, and 1 μA maximum beam current, the best electron gun characteristics were analysed. Optimum brightnesss is 2.5×105 A/cm2 sr. The product of crossover diameter and beam divergence semiangle is larger than 3.4×10−6 cm rad. Developed LaB6 guns have the following characteristics: crossover diameter is about 15 μm, beam divergence semiangle at 90% of the center intensity is larger than 3×10−3 rad and brightness varies from 7×104 to 6×105 A/cm2 sr with emission current conditions. Special features of this gun are the 480 μm tip radius and <110≳ orientation. An electron optical column for a variably shaped beam was constructed with this electron gun. Beam intensity instability for this column was smaller than ±2%/8 h without alignment or brightness servos.
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29.25.Bx Electron sources
41.75.Fr Electron and positron beams
79.40.+z Thermionic emission

Ti getter study

D. Edwards and C. Lanni

J. Vac. Sci. Technol. 17, 1373 (1980); http://dx.doi.org/10.1116/1.570674 (2 pages)

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It has been shown that significantly lower ultimate pressures in a baked vacuum chamber are obtained if the Ti is flashed onto the getter chamber walls after the bakeout, when the entire system has cooled to room temperature, rather than flashed onto the chamber walls with the system hot as at the end of the bakeout with the system nominally at the bakeout temperature.
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07.30.-t Vacuum apparatus

Nonresonant charge transfer in ion–surface scattering

R. S. Bhattcharya

J. Vac. Sci. Technol. 17, 1375 (1980); http://dx.doi.org/10.1116/1.570675 (2 pages)

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The role of nonresonant charge exchange mechanisms in the formation of the charge state of ions backscattered from polycrystalline surfaces is further explored.(AIP)
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79.20.-m Impact phenomena (including electron spectra and sputtering)
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

SnO2+Al2O3 continuous dynode electron‐multiplier

P. W. Mahajan and S. V. Bhoraskar

J. Vac. Sci. Technol. 17, 1376 (1980); http://dx.doi.org/10.1116/1.570676 (2 pages)

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The use of a new combination of tin oxide and aluminium oxide films as electron multiplier dynodes is reported. The tin oxide serves as a semiconducting material whose resistivity is increased due to the presence of the aluminium oxide which acts as a secondary emitter.(AIP)
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84.47.+w Vacuum tubes
82.45.-h Electrochemistry and electrophoresis

Outgassing characteristics of TiC and TiB2 coated graphite

J. H. Craig

J. Vac. Sci. Technol. 17, 1377 (1980); http://dx.doi.org/10.1116/1.570677 (2 pages)

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Two coatings to minimize high‐Z contaminant release in plasma devices are TiB2 and TiC chemically vapor deposited on Poco graphite. Total outgassing rate and mass spectra measurements have been conducted on the materials at room temperature, 100°C and 250°C.(AIP)
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
66.30.J- Diffusion of impurities
52.75.-d Plasma devices
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

A simple method of end‐point determination for plasma etching

M. L. Hitchman and V. Eichenberger

J. Vac. Sci. Technol. 17, 1378 (1980); http://dx.doi.org/10.1116/1.570678 (4 pages) | Cited 3 times

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It is shown that end‐point detection in plasma etching can be accomplished simply and without the use of sophisticated and expensive equipment by using a commercial vacuum gauge to monitor the effluent gas.
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81.65.-b Surface treatments
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
52.70.-m Plasma diagnostic techniques and instrumentation
68.60.-p Physical properties of thin films, nonelectronic

Design for a high temperature, high vacuum evaporation furnace

K. W. West

J. Vac. Sci. Technol. 17, 1382 (1980); http://dx.doi.org/10.1116/1.570679 (2 pages)

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An evaporation furnace capable of temperatures greater than 1700°C in high vacuum, with temperature monitoring, is described. The assembled furnace can be inserted through a standard 2.75 in. vacuum flange.
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07.20.Hy Furnaces; heaters
68.55.-a Thin film structure and morphology
81.10.-h Methods of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation

Removal of volatile materials from forepump oil

Paul P. Nicole

J. Vac. Sci. Technol. 17, 1384 (1980); http://dx.doi.org/10.1116/1.570680 (1 page)

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A method of clearing condensable vapors from forepump oil is described. Air is bubbled though the oil reservoir removing volatile material from the oil and allowing continuous pumping of materials by non‐vented pumps.
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07.30.Kf Vacuum chambers, auxiliary apparatus, and materials
07.30.Cy Vacuum pumps
07.30.Bx Degasification, residual gas

Vacuum applications of metal foams

B. R. F. Kendall

J. Vac. Sci. Technol. 17, 1385 (1980); http://dx.doi.org/10.1116/1.570681 (1 page)

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Possible applications of metal foam materials in vacuum systems are described. Copper foam, for example, is highly porous, easily shaped and strong, easily brazed or soldered, and has good thermal conductivity. The molecular‐flow conductance of metal foams is important in vacuum applications.
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07.30.Kf Vacuum chambers, auxiliary apparatus, and materials
06.90.+v Other topics in metrology, measurements, and laboratory procedures (restricted to new topics in section 06)
06.60.Vz Workshop procedures (welding, machining, lubrication, bearings, etc.)

Secondary Ion Mass Spectrometry: Sims II, edited by Benninghoven, Evans, Jr., Powell, Shimizu, and Storms

C. W. Magee

J. Vac. Sci. Technol. 17, 1386 (1980); http://dx.doi.org/10.1116/1.570682 (1 page)

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Abstract Unavailable
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01.30.-y Physics literature and publications
07.75.+h Mass spectrometers
79.90.+b Other topics in electron and ion emission by liquids and solids and impact phenomena (restricted to new topics in section 79)
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