摘要:

It is possible to greatly reduce the physical dimensions of cold cathode vacuum gauges by increasing the efficiency of the magnetic circuit. The work described in this paper was undertaken to establish the limit to which miniaturization could be carried. It is concluded that a gauge 18.5 mm high and weighing 25 g is close to the practical lower limit for gauges of the geometry tested.

ISSN:0022-5355    

DOI:10.1116/1.1317084

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

We have investigated the capability of the electron beam evaporation technique for producing thin W films having properties suitable for application as first-level metallization in refractory MOS (RMOS) devices. The apparatus consisted of a sputter-ion pumped 18-in. diam UHV station, 6-kW e gun, and a quartz crystal rate monitor. The evaporation process employs low background pressures(1−3×10−7 Torr), substrate heating (200–700 °C), a preevaporation step, and evaporation at rates of 100–500 Å/min. Maximum throughput is 16 1(14)-in. diam silicon slices per run. Using substrate temperatures of 500–700 °C, we have been able to produce mechanically stable, adherent films having a resistivity of 7–8 μΩ cm and a sheet resistance of ∼ 0.08 Ω/□ (for 9000-Å film). “Cold”-deposited films (>1000 Å thick) having a high resistivity of 40–50 μΩ cm can be annealed at 1000 °C to resistivity of 10–15 μΩ cm. The films are single-phase bcc W with a small grain size of 0.1–0.2 μ. Low resistivity films (deposited above 550 °C) are associated with a large degree of microstructural perfection, and have small tensile stresses(3−7×109dyn cm−2). The films possess, excellent high-resolution etchability, and were found to be compatible with MOS structures provided care is exercised during the deposition.

ISSN:0022-5355    

DOI:10.1116/1.1317085

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

A feedback-controlled three-source evaporator system is described. Its purpose is the preparation of multilayered thin-film specimens to be used for the study of diffusion in ternary alloys. It is shown that, with this system, it is possible to prepare thin films representing a variety of binary or ternary diffusion microcouples with specified layer thickness and specified composition ratios of the alloy components. The uniformity of thickness of each layer, essential for diffusion studies, was confirmed by the appearance of satellite intensity maxima around x-ray fundamental reflections from an AgAuPd solid solution alloy in this system.

ISSN:0022-5355    

DOI:10.1116/1.1317086

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

In this paper a new technique for high speed anodization in a dc oxygen discharge is reported. A 0.0025-cm-diam wire biased 50 V positive with respect to the anode caused a ten- to fifteenfold increase in the anodization rate. Rates as high as 30 A/ min were observed with a sample current denisty of 1.15mA/ cm2. With a current density of0.21  mA/ cm2the Faraday efficiency was 15%. It is postulated here that the observed effects are due to increased surface ionization of adsorbed atomic oxygen.

ISSN:0022-5355    

DOI:10.1116/1.1317087

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

A process which causes repeatable microtopographical changes in the oxide cathode coating of an electron tube has been investigated. This process, which is carried out by heating the cathode inCO2, reduces surface roughness and the incidence of loose particles. The scanning electron microscope in conjunction with electrical measurements was used to document and assess the repeatability of these microtopographical changes in the cathode and the resulting changes in electrical performance. Increasing the time of heating (contact time) inCO2from 1 to 30 rain was found to increase the degree of microtopographical change but also to decrease the triode pulse emission.CO2treatment leaves the Richardson work function of the cathode unchanged at ∼ 1.1 eV, indicating that no significant, change in the chemistry of the cathode was caused by this treatment. The lower emission capability afterCO2treatment was due to decreased values of the Richardson constant. The change is logically attributable to the observed decrease in the micro-scale surface roughness of the coating. Decreases in the Richardson constant due toCO2treatment ranged from ∼ 35% at a contact time of 2 min to ∼ 90% at a contact time of 30 min.

ISSN:0022-5355    

DOI:10.1116/1.1317088

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The pressure reduction method commonly used in monitoring gas composition at relatively high pressures is not adequate for application to sputter gas analysis. Desorption phenomena in the ion source of the spectrometer and adsorption phenomena in other parts of the reduction stage cause extraneous errors in the partial pressure measurement of most of the gases of interest. A successful attempt has been made to perform gas analysis without a reduction stage. Analysis of the influence of ion-atom (molecule) scattering on the performance of ionizer, extractor, and analyzer for different types of residual gas analyzers shows that a miniquadrupole offers the best prospects for this special purpose. Comparative data for a quadrupole and cycloidal mass spectrometer operating at an argon pressure of2.10−3Torr are given. Resolution, sensitivity, and linearity of the quadrupole have been determined at sputtering pressures(10−3–10−2 Torr). The resolution remains quite satisfactory(M/ΔM = 2.5 Mwhen ΔMis measured at 50% peak height). The sensitivity decreases with increasing pressure. However, at5.10−3Torr nitrogen partial pressures of10−8Torr can still be detected. Simultaneous measurement of the sputter gas atmosphere by the pressure reduction method and the quadrupole during the deposition of gold in a planar rf sputtering system shows that the quadrupole which is directly connected to the sputter chamber allows a more accurate identification of the background gases.

ISSN:0022-5355    

DOI:10.1116/1.1317089

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Under idealized conditions, the relative volatility of the molecular distillation of a binary mixture is higher than that of equilibrium distillation by a factor of(M2/M1)1/2, whereM2andM1are the molecular weights of the less and more volatile components, respectively. But in practice, this advantage of molecular distillation is usually not observed experimentally. This deficiency of separation efficiency of molecular distillation is now explained by computing the effects of surface cooling, surface depletion of the more volatile component, and the nonideality of the liquid mixtures. It is noted that shorter exposure time of the liquid surface is desirable for the design of an efficient molecular still. For the estimation of the separation efficiency of molecular stills whose exposure time of the liquid surface is not controlled mechanically, the surface renewal model is considered to be more realistic.

ISSN:0022-5355    

DOI:10.1116/1.1317090

出版商:American Vacuum Society    

年代:1973

数据来源: AIP