摘要:

By an insulating film we mean one which passes little or no electric current on the application of a voltage across it. If the film were a single crystal of pure material this would require it to have a bandgap of 2 eV or more, so that there would be few intrinsic carriers over a practical temperature range. In practice insulating films are often amorphous and the usual energy-band description cannot be applied; in such a film the density of charged carriers may be relatively high and the insulating behavior arises from their having zero or very low mobility in an applied field. The presence of these localized carriers may affect the polarizability, and therefore the dielectric properties, of the film. Furthermore, whether or not the film exhibits insulating properties will depend on the nature of the contacts made to it in order to measure its electrical conductivity. This paper considers these matters and reviews present applications of dielectric films.

ISSN:0022-5355    

DOI:10.1116/1.1316552

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

Grown thin films ofSiO2play an important role in the performance and stability of silicon insulated gate field effect transistors, bipolar transistors, and diodes used in modern integrated circuits. The principal properties of theSi–SiO2system which can influence device characteristics are fixed charge, interface states and drift. Fixed charge and interface states can adversely affect device characteristics like gain, noise, junction reverse currents, and junction breakdown voltage, while drift undermines the stability of these device characteristics. Our present understanding of some of the chemistry and physics of theSi–SiO2system pertaining to device performance and stability will be reviewed. The metal-oxide–silicon capacitor has been the principal measurement tool used in this work. Its operation and how it was used to determine the oxide growth conditions, annealing treatments, and other processing required to get low fixed charge and interface state densities and minimum drift will be emphasized.

ISSN:0022-5355    

DOI:10.1116/1.1316530

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.1316532

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

Recent advances in our understanding of the phenomena that determine the leak rate in demountable vacuum seals are presented. The description includes a survey of recent investigations of the vacuum sealing process and a comparison of the results obtained by various research groups. A systematic interpretation of the sealing mechanism is presented, in which the phases that may occur in the sealing process are summarized, and the characteristics of the tightening curve, releasing curve, accommodation, and normal sealing stages are established. The concept of sealing ability and tightening index are defined and used to explain the characteristic leak rate graphs. The influence of the size and profile of the surface roughness, waviness, local imperfection (scratches), seal width, and helium pressure are summarized or discussed. In conclusion, a system of concepts, graphs, and equations for expressing the operation of seals is presented and a way in which these should be used as a basis for classification and standardization of demountable vacuum seals is proposed.

ISSN:0022-5355    

DOI:10.1116/1.1316537

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

A new configuration for high-temperature heat shielding has been developed and tested; the shields are several times as efficient as those in common use. The configuration consists of a multiturn, close-spaced spiral, wound out of thin tantalum sheet. Conduction losses around the spiral are negligible. Turn-to-turn spacings down to about 100 μm are maintained using low loss spacers; the conduction loss of the spacers sets the limit on the design. A theory is presented for the design of vacuum heat shielding; fundamental limits are considered. Two applications are a mass spectrometer Knudsen cell generating a neutral carbon atomic beam at 2400 K using a total input power of only 165 W, and a high-temperature direct-vaporization ion source generating a10−6-Agallium beam with a total input power of only 110 W. An attractive future application might be large high-temperature ovens, where large amounts of power have previously been required.

ISSN:0022-5355    

DOI:10.1116/1.1316567

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

A discussion is presented of the influence of ion–neutral collisions downstream from an orifice through which ions from a glow discharge are being extracted. The effective pressure on the low-pressure side of the orifice is treated as the sum of a static pressure (determined from pumping speed and orifice conductance considerations) and a localized beam pressure which is due to the neutral species effusing through the orifice with the ions. It is shown that in most experimental situations the beam pressure has a much greater influence on a collimated ion beam than does the static pressure. Some experimental results which support this conclusion are presented. These results were obtained using a system which was designed to observe the ionic species in a sputtering glow discharge.

ISSN:0022-5355    

DOI:10.1116/1.1316580

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

The adjustment of individual resonator frequencies is essential in the process of manufacturing monolithic crystal filters (MCF). This paper will discuss the design and performance of a vapor plating facility for the automatic adjustment of these resonator frequencies in the process of manufacturing eight resonator MCF’s. This facility is designed to adjust eight filters (64 resonators) per pump-down cycle. Design of the pumping system, vacuum chamber, and electronic control system are discussed in detail. This involves the interfacing of an electronic control system with the vacuum station in order to achieve precise positioning and dynamic frequency measurement of the devices being plated, as well as variable plating rate at critical stages of adjustment. The system may be programmed automatically by tape or operated manually.

ISSN:0022-5355    

DOI:10.1116/1.1316584

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

Aluminum was evaporated from a 12-kW, 180° bent-beam gun onto substrates located 25 cm from the hearth. The substrate temperature was varied from 100° to 450°C and the deposition rate from 1000 to 100 000 Å/min. The aluminum was evaporated from the water-cooled copper hearth and from intermetallic and carbon hearth linears within the copper hearth. The charge remaining in the hearth and the films were analyzed and contamination levels are reported. The useful remaining life of the liners was also determined. The surfaces and structures of 10 000 Å, thick films were examined using a scanning electron microscope, and found to be a function of deposition rate and substrate temperature.

ISSN:0022-5355    

DOI:10.1116/1.1316601

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

Vacuum arcs are discussed from the aspect of vapor sources on the basis of a recent investigation of various ejected species, such as metal atoms, ions and molten metal particles, and their energy or velocity spectra for about 30 different metals and alloys.

ISSN:0022-5355    

DOI:10.1116/1.1316620

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.1316624

出版商:American Vacuum Society    

年代:1972

数据来源: AIP