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Jul 1972

Volume 9, Issue 4, pp. 1133-1228


Traditional Main-Frame Memories, Cores, Wires, and Films

Hsu Chang

J. Vac. Sci. Technol. 9, 1133 (1972); http://dx.doi.org/10.1116/1.1317003 (2 pages)

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68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Semiconductor Memory—a 1972 Look

Tudor R. Finch

J. Vac. Sci. Technol. 9, 1135 (1972); http://dx.doi.org/10.1116/1.1317004 (10 pages) | Cited 1 time

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During the past 15 yr design of digital systems has been guided, and directed in large part, by the rapidly evolving solid state technologies. From transistor to silicon LSI and through several generations of magnetic core memories, the combined cost, speed, and reliability improvement has been several orders of magnitude for both logic and memory. It is now reasonably clear that such cost-performance capability will be considerably extended through more extensive use of LSI, in particular with 20–200 nsec semiconductor memories. Realization of such cost and performance improvement will have a major impact on digital systems.
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85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology

Magnetic Bubble Devices

A. H. Bobeck

J. Vac. Sci. Technol. 9, 1145 (1972); http://dx.doi.org/10.1116/1.1317005 (6 pages) | Cited 2 times

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The properties of cylindrical magnetic “bubble” domains have been extensively described in the literature. Our understanding of bubble technology has now progressed to the point where it is possible to undertake the design and evaluation of specific bubble systems. Bubble domains, cylindrical islands of reverse magnetization, exist in specially prepared single crystal uniaxial magnetic platelets and epitaxial films. These domains are manipulated by localized magnetic fields generated by currents applied to conductors (conductor access) or inplane fields applied to structured permalloy patterns (field access). An important application of bubbles will be in bulk storage. Study of propagation circuits indicates that reasonable field access memory design objectives are (1) in-plane field frequency, 0.1–10 MHz; (2) in-plane field, 10–30 Oe; (3) storage density, 1.5–10 megabits∕in.2; (4) bits∕chip, 10 000–100 000.
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85.70.-w Magnetic devices

Promise of Optical Memories

Jan A. Rajchman

J. Vac. Sci. Technol. 9, 1151 (1972); http://dx.doi.org/10.1116/1.1317006 (9 pages)

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Holographic and various other techniques may make it possible for the first time to store billions of bits on a permanent and shelvable record so that there is full random addressing in microseconds both for recording and reading out. Such a mass optical memory, with the capacity and permanence of disks, but without any mechanical motion, and the accessibility of cores, may replace both and thereby greatly improve the performance and simplify the architecture and operation of computers. The concept is based on compounded selection, an internal electrically and light addressable matrix array, and holographic storage on an erasable and reusable continuous recording medium. The progress toward implementation of the concept and the remaining challenges will be discussed, including specific aspects of light deflection and modulation, the over-all optical system, and the storage medium.
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42.79.Vb Optical storage systems, optical disks

The Physics of Some Superconducting Devices

Ivar Giaever

J. Vac. Sci. Technol. 9, 1159 (1972); http://dx.doi.org/10.1116/1.1317007 (7 pages)

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This is a brief review of some of the more common superconductive devices suitable for computer applications. None of the devices have emerged beyond the laboratory stage, mainly because of the low temperature requirements. Because of the increased sophistication in the integrated semi-conducting technology, it appears that superconducting devices can only succeed when their function is unique; for example, the ac Josephson effect is under serious consideration as a tool to determine the international voltage standard.
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85.25.-j Superconducting devices

Charge Transfer Devices

M. F. Tompsett

J. Vac. Sci. Technol. 9, 1166 (1972); http://dx.doi.org/10.1116/1.1317008 (16 pages) | Cited 5 times

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This is a review describing the use of charge transfer devices for digital memory, analog delay, and image sensing. Short descriptions of different types of charge-coupled devices and MOS bucket-brigade devices are presented. Those factors such as transfer inefficiency, noise, and dark current which affect the performance of these devices in the above applications are discussed. Various possible organizations of charge transfer devices to serve different functions are described. Many charge transfer devices have been fabricated and already indicate a high degree of achievement. Transfer inefficiencies per transfer in the range 10−3 to 10−4 have been measured. Finally, it is projected that charge transfer devices will rapidly find their way into certain analog delay, image sensing, and digital applications.
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85.30.-z Semiconductor devices

Amorphous Memories and Bistable Switches

David Adler and Simon C. Moss

J. Vac. Sci. Technol. 9, 1182 (1972); http://dx.doi.org/10.1116/1.1317009 (9 pages) | Cited 6 times

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The two types of switching phenomena that characterize thin films of covalent amorphous solids are described in detail. Several mechanisms that can account for these phenomena are presented and analyzed in view of recent experimental data. Two applications of bistable switching to computer memories are discussed—the electronically alterable Read-Mostly Memory (RMM) and the mass optical memory (MOM).
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85.30.-z Semiconductor devices
42.79.Vb Optical storage systems, optical disks

Silver Chloride Vacuum Seals

Mohammad Aslam

J. Vac. Sci. Technol. 9, 1191 (1972); http://dx.doi.org/10.1116/1.1317010 (3 pages)

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Silver chloride has been successfully used in vacuum seals and vacuum valves. Sealing procedures are reviewed and a comprehensive bibliography on the subject presented. A method to improve the operating speed of silver chloride vacuum valves is suggested. Another use of silver chloride seals for electrical feed-throughs in the laboratory is briefly mentioned. A modified technique for seal formation is reported and its usefulness is briefly described.
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07.30.Kf Vacuum chambers, auxiliary apparatus, and materials

Thickness Dependence of Electron Mobility of InSb Films

H. H. Wieder

J. Vac. Sci. Technol. 9, 1193 (1972); http://dx.doi.org/10.1116/1.1317011 (4 pages) | Cited 4 times

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The thickness dependence of the room temperature electron mobility of InSb films is shown to be in good qualitative but poor quantitative agreement with theoretical mobility limiting models based on diffuse or specular surface scattering. An alternative model based on the presence of a surface accumulation layer on films with bulklike properties is shown to provide a fair quantitative agreement with experimental data.
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73.50.Dn Low-field transport and mobility; piezoresistance
73.61.Ey III-V semiconductors

Temperature Rise during Film Deposition by rf and dc Sputtering

S. S. Lau, R. H. Mills, and D. G. Muth

J. Vac. Sci. Technol. 9, 1196 (1972); http://dx.doi.org/10.1116/1.1317012 (7 pages) | Cited 11 times

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The temperature rise during film deposition by rf sputtering of Ta, Au, and Pd films and dc sputtering of Ta films has been investigated. The film temperature was measured for various cathode to anode distances, as a function of applied power used for sputtering and sputtering time. It was found that by sputtering from water-cooled cathodes at power levels between 0.1 and 2 kW, the contribution due to radiation from the plasma and the cathode is negligible. To a first approximation, heating is caused in varying amounts by the kinetic energy of the sputtered atoms, the latent heat of condensation of the sputtered atoms, and electron bombardment. The film temperature also depends on the optical emissivity of the deposited materials causing the temperature of films with higher emissivities such as Pd to remain significantly lower for comparable sputter times and power. For dc sputtering from an uncooled cathode, it was estimated that radiation from the cathode contributes significantly to the heating of the sputtered films.
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81.15.Cd Deposition by sputtering

Two Kilometers at 10−10 Torr. The CERN Intersecting Storage Rings for Protons

E. Fischer

J. Vac. Sci. Technol. 9, 1203 (1972); http://dx.doi.org/10.1116/1.1317013 (6 pages) | Cited 2 times

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The Intersecting Storage Rings (ISR) in Geneva are a new research facility for experiments with colliding proton beams of energies of up to 28 GeV and intensities of up to 20 A. The ISR vacuum system consists of two interlacing doughnuts formed by ellipitical pipes 160×50 mm and circular pipes of 160 mm diameter, of a total length of 2 km. The chambers are made out of stainless steel and can be baked in situ at 200–300 °C. An average pressure of 10−10 Torr has been attained. This is necessary in order to achieve the required beam life of several days. At the intersecting regions where the proton-proton collisions are being observed and where proton-gas collisions produce a disturbing background, equivalent nitrogen pressures of 10−11 Torr are required and have been actually achieved. Experiences are reported on the construction, commissioning and operation of this vacuum system.
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29.20.db Storage rings and colliders
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials

Structure of the (0001) Surface of α-Alumina

P. S. P. Wei and A. W. Smith

J. Vac. Sci. Technol. 9, 1209 (1972); http://dx.doi.org/10.1116/1.1317014 (5 pages) | Cited 3 times

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The (0001) surface of α-Al2O3 has been studied by low-energy electron scattering. Interesting features in the LEED pattern, the energy loss spectrum and the LEED intensity profile, have been observed. The results are discussed in terms of the characteristics of the corundum structure.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)

The Problem of the Compounding of Transmission Probabilities for Composite Systems

L. Füstöss and G. Tóth

J. Vac. Sci. Technol. 9, 1214 (1972); http://dx.doi.org/10.1116/1.1317015 (4 pages) | Cited 1 time

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A clear definition of the transmission probability depending on the flow direction in systems of varying cross sections is given. A method is shown which makes it possible to determine approximately the transmission probability of complex systems. The accuracy of the approximations is refined by proper correction factors. A descriptive concept of flow resistance is introduced. It helps to determine the validity range of the obtained formulas and the dependence of the accuracy on the parameters.
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47.60.-i Flow phenomena in quasi-one-dimensional systems

Hydrogen and Nitrogen Desorption Phenomena Associated with a Stainless Steel 304 Low Energy Electron Diffraction (LEED) and Molecular Beam Assembly

A. M. Horgan and I. Dalins

J. Vac. Sci. Technol. 9, 1218 (1972); http://dx.doi.org/10.1116/1.1317016 (9 pages) | Cited 2 times

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The rates of hydrogen desorption from the walls of a standard LEED stainless steel vacuum chamber isolated from the ion pump have been measured using an oxygen-free copper orifice of known conductance, which acts as the final focussing slit in a molecular beam assembly, and found unacceptably high for the maintenance of a clean metal single crystal surface. The causes are discussed and the rates of desorption are presented after the stainless steel apparatus had been subjected to vacuum degassing at 850–950 °C in a vacuum furnace at pressures ≤10−5 Torr. Desorption rates are decreased ∼130 times. Rates of desorption of nitrogen from Varian post-acceleration type two and three grid LEED optics screens (P-4 CR 422 phosphor) have been measured. Possible displacement reactions with residual hydrogen, small quantities of which are adsorbed during nitrogen desorption, are discussed. It is concluded that the two processes are independent of each other. Contamination of the single crystal samples with the nitrogen desorbed for the LEED screen is also discussed. Brief reference is made to the adsorption properties of stainless steel 304 with special reference to hydrogen and nitrogen.
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68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials

On Uniformity of Film Thickness on Rotating Substrates

B. S. Ramprasad, T. S. Radha, and M. Ramakrishna Rao

J. Vac. Sci. Technol. 9, 1227 (1972); http://dx.doi.org/10.1116/1.1317017 (2 pages) | Cited 4 times

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Abstract Unavailable
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81.15.Aa Theory and models of film growth
68.55.-a Thin film structure and morphology
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