摘要:

Titanium films, 1 μm thick were electron‐beam evaporated onto polyethylene (PE) that had been pretreatedinsituby 2 keV Ar+bombardment. A measure of the film adhesion was obtained by measuring the pull strength required to remove the Ti films. A strong dependence of the adhesion on the ion dose was found. The pull strength had a maximum of approximately 20 MPa after a dose of 6×1014ions/cm2but decreased for higher ion doses. Without any ion bombardment prior to deposition, the adhesion was very poor with a pull strength of approximately 2 MPa. XPS analysis was used to examine the effect of the ion bombardment on the chemistry of the PE substrate and the Ti/PE interface. Untreated PE samples were contaminated with surface impurities and probably also with low molecular weight hydrocarbons. As the adhesion is maximized, most of the impurities are removed by the ion bombardment. The strong adhesion is suggested to be due to formation of a carbidelike Ti–C interfacial layer, detected by XPS.

ISSN:0734-2101    

DOI:10.1116/1.572460

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

Materials such as tungsten, molybdenum, stainless steel, etc., which have low solubility in mercury (Hg) are difficult to be wetted or coated with the liquid metal. This paper describes a general technique for wetting and coating such metals with Hg. The method involves plasma etching the substrate and making the liquid metal interact with the plasma before it contacts the substrate surface, by delivering it to the substrate through the glow discharge, to successfully wet the above metals. Elkonite (70% W and 30% Cu) was also wetted successfully by this technique. A model has been presented to qualitatively explain the observed results. The discharge is postulated to create reactive species on the substrate surface and to produce reactive Hg species as Hg travels through the plasma. Further, the surface free energies of the substrate and the liquid metal are altered suitably to favor wetting and surface complexing as described by Young’s equation.

ISSN:0734-2101    

DOI:10.1116/1.572461

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

The gain of channel electron multipliers (CEM) decreases rapidly during experiments which involve exposure of samples to ∼10−8Torr H2O during electron bombardment—an environment which very effectively oxidizes semiconductors. In subsequent experiments it was found that reoxidation of samples of CEM glass (it is subject to reduction treatment during manufacture) occurs when it is exposed to the same set of conditions. We discuss the possible influence of this on the gain degradation commonly observed as a function of total counts.

ISSN:0734-2101    

DOI:10.1116/1.572463

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

A conventional residual gas analyzer was equipped with an ion‐electron converter as particle detector and tested in tritium‐containing environments. Substantial advantages can be asserted for this setup: high dynamic range, easy regenerability by baking without detrimental effects on the multiplier, insensitivity to exposure to reactive gases, and inexpensive replacement.

ISSN:0734-2101    

DOI:10.1116/1.572464

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

Surface conditioning by rf‐assisted dc glow (RG) discharges has been studied in a stainless steel vessel in order to optimize the rate of surface deoxidization via water formation. This is the simplest way to decontaminate the almost carbon‐free surfaces of plasma devices which have been exposed to air after a prolonged operation in hydrogen. This rate depends strongly on the wall temperatureTW, the pump speedSp, the discharge currentIRG, and the hydrogen pressureP2. It is small at ambient temperature; the conditioning should be made atTW>100 °C. Surface oxygen is removed, even at room temperature, when 1% to 2% of methane is added to the hydrogen. Carbon monoxide is formed and evacuated. The addition of He or Ne does not accelerate the oxygen removal from reoxidized surfaces. An equation derived from a simplified model describes the parametric dependences of the water release well. The occurrence of arcs during RG discharges depends on wall conditioning; they are not observed after a prolonged bakeout at 200 °C. The problems which arise when a residual gas analyzer is used to measure the partial pressures of water, carbon oxides, and hydrocarbons in hydrogen are addressed, and a conditioning technique which reduces the resulting errors is described.

ISSN:0734-2101    

DOI:10.1116/1.572465

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

By extending earlier ideas and introducing new ones in this paper, we relate observable rf discharge parameters to the plasma etch characteristics of rate, selectivity, and anisotropy. The ion energy transport ‘‘ellipsoid’’ generated by the electric field across the plasma sheath is shown to induce anisotropic etch reactions and, under certain circumstances, to ‘‘enhance’’ the intrinsic chemical etch selectivity. The plasma sheath electric field is shown to be determined by observable rf discharge parameters. The rf discharge is reduced to an equivalent circuit, which relates the time averaged plasma body and sheath electric fields to the rf discharge parameters of plasma geometry, current or power and discharge excitation frequency. We find two regimes of excitation frequency, for otherwise identical conditions, generating much larger sheath electric fields below than above the ion plasma frequency (∼1 MHz). Fixing the plasma geometry and etch gas chemical composition is identified as central to obtaining simply behaved and reproducible etch characteristics. At comparable etch anisotropy, the only practical distinction between the etch characteristics of ‘‘high’’ pressure ‘‘plasma etching’’ and ‘‘low’’ pressure ‘‘reactive ion etching,’’ is that the former is capable of significantly higher etch rates and selectivities than the latter.

ISSN:0734-2101    

DOI:10.1116/1.572466

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

Erosion grooves are known to develop on a surface of a planar magnetron sputtering target in the course of its use, causing the rate of deposition per unit power applied to the target (rate efficiency) to decrease with progressing erosion. It is shown that for a given target material there is a reproducible empirical correspondence between the rate efficiency and the groove depth. Once established, this correspondence offers a simple way for estimating thicknesses of the films deposited onto stationary and rotating substrates.

ISSN:0734-2101    

DOI:10.1116/1.572467

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

An oblique ion milling simulation method is proposed in which etching and redeposition at the pattern side wall are taken into account. The effective etching rate at the pattern side wall is determined as the difference between the etching rate given by the angular dependency and the redeposition rate. The redeposition rate is assumed to be proportional to the etching rate of the material to be etched at the flat surface. A pattern edge profile simulation is carried out for an oblique ion milling of silicon. The simulation results agreed well with the experimental results with a relatively large ion beam incident angle.

ISSN:0734-2101    

DOI:10.1116/1.572468

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

To optimize the procedure for evaporating a metal film onto a sphere, calculations of the film thickness distribution for various motions of the sphere have been carried out. These calculations, including shadowing effects of sphere support rods, are presented in this paper. Also, an apparatus and procedure for the evaporative coating of a sphere are described. A comparison of measured thickness with the calculated values is made for one example of sphere motion. The implications of the calculated results for coating techniques are discussed.

ISSN:0734-2101    

DOI:10.1116/1.572469

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

Formative processes of the series crossed‐field discharges in vacuum switches were investigated, and pulsed discharges were found feasible for switch‐pressure measurement, when solid surfaces within switches are clean. The fact that a vacuum switch is a small, sealed device, causes problems in switch‐pressure measurement, to which serious conditions for performance are charged. To solve the problems, pulsed discharges were investigated. The discharge in a switch, identified previously as a series discharge consisting of an inverted magnetron and a magnetron, was generated by rectangular high voltage at amplitudeVd. Discharge currents in formative phases were measured and analyzed. Formative processes were revealed to be composed of triggering and growth. At a largeVdvalue, the discharges are triggered immediately after the stepped voltage application. Instantaneous discharge triggering assures high reliability in pressure measurement. At smallVdvalues, times required for triggering are delayed and scattered. In the growth phase, discharge currents proceed to increase in a reproducible pattern, and become saturated. Then they begin to decrease, resulting from pressure decreases due to the pumping effect of discharges. A current increase in the growth phase is always quick, and a decrease after saturation is slow. Magnitudes of the saturation currents are distributed concentratedly. This causes good precision in measurement, typically with errors less than 10% of the measured values. The time intervals necessary to establish the pulsed discharges and the pumping effect to change pressures were analyzed. The measurement range was found to cover a low pressure, down to 1×10−4Pa, with a pressure decrease of less than 20%, when pumping speed is 4.2 l/s, which is the maximum experimental value. Thus, pulsed series crossed‐field discharges were found to be feasible for switch‐pressure measurements, when switch interior surfaces are clean.

ISSN:0734-2101    

DOI:10.1116/1.572470

出版商:American Vacuum Society    

年代:1984

数据来源: AIP