摘要:

Ion implantation has been developed to the point where it is used in production of silicon devices for integrated circuit applications. This paper reviews the basic factors influencing the electrical behavior of dopant species implanted in silicon. Implantation in compound semiconductors, primarily III–V compounds, is not as well defined, but clear guidelines can be established. One of the key factors in untangling implanation phenomena was the use of backscattering and channeling effect measurements with MeV particles to determine the amount and anneal behavior of lattice disorder and the lattice position of dopant atoms. This technique has now been applied to the analysis of layer structures, because it provides both mass information and depth distributions (≈200 Å resolution down to ≈1 μ). We have investigated properties of dielectric layers [SiO2,Si2N4, andAl2O3), magnetic films, and diffusion in both semiconductors and oxide layers.

ISSN:0022-5355    

DOI:10.1116/1.1316632

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.1316636

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.1316639

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

A number of problems arise in the design, commissioning and subsequent running of the vacuum system of a large synchrotron. The problems dealt with are (a) high water desorption from ferrite materials, (b) the use of a data logging computer for ion pump starting and pressure monitoring, (c) the protection of the system due to turbomolecular pump set failure when running unattended, (d) the reconditioning of ion pumps, and (e) radiation damage to early design vacuum chambers and outgassing due to synchrotron radiation.

ISSN:0022-5355    

DOI:10.1116/1.1316644

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

A 60-MeV superconducting proton accelerator is now being constructed at Karlsruhe as a pilot project for a larger accelerator. This paper discusses vacuum aspects of a superconducting linac in regard to surface contamination, sparking, radiation damage, etc., and presents a brief description of the pilot cryostat and gives some experimental results. Special features of the cryostat are the use of a two vacuum system in which no uhv flange has any contact with superfluid helium and the use of cooled ion pumps as an integral part of the rf structure.

ISSN:0022-5355    

DOI:10.1116/1.1316659

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

The pumping action of titanium is considerably enhanced if the active layer is made on a cold surface. High pumping speed of10 liters/sec⋅cm2for usual gases, capacity at saturation of about1016 molecules/cm2, limit pressure down to10−10 Torr, and good cleanliness make it very attractive for a number of applications. Titanium monoxide TiO has very similar properties at low temperature and, in addition, can pump argon. Titanium pumping is particularly suited to big-size installations with very specific problems like the nuclear fusion research apparatus and the space simulation chambers. Examples of these two cases are described.

ISSN:0022-5355    

DOI:10.1116/1.1316669

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

An oil-free vacuum system capable of achieving vacuum levels of10−6 Torrfor in-pile experiments has been constructed at the pool-type Battelle Research Reactor (BRR). The pumping system which is mounted on a moveable bridge above the pool surface, consists of a 7500 liter/sec titanium sublimation pump and two 350-liter/sec triode-type ion pumps; system roughing is accomplished with a roots-type blower with a double-walled liquid nitrogen trap. Nine meters of 20.3-cm (8-in.) diam vacuum piping connect the pumping system to a test chamber at the core level. Test chamber geometry can be varied to fit either a7.62×7.62-cmtest cell or the core face. Neutron fluxes of2×1013 neutron/cm2⋅sec(thermal) and1×1013 neutron/cm2⋅sec(fast) are available and the maximum gamma rate is108 R/h. Adjustments of desired gamma/neutron ratio are made by employing appropriate shielding at the core face. Irradiation effects on the performance of electro-mechanical components for space nuclear power systems have been studied at elevated temperatures (620–820 K) and a full-scale nuclear fueled thermionic diode is currently being prepared for irradiation in the system.

ISSN:0022-5355    

DOI:10.1116/1.1316685

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.1316686

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

A trailer-mounted two-stage booster mechanical pumping system has been constructed for use in evacuation of large vacuum vessels in remote locations. The pumping system is composed of three nominal 1500-cm air-cooled Roots blowers and four nominal 150-cfm mechanical pumps. It includes a high conductance cryogenic baffle, a self-contained helium leak detection station with a high speed oil diffusion pump, a liquid cryogenic system for supply of cryogenic fluids to the two cryogenic traps, and dry gas for use in backfilling of vessels as required. A programmed start-up and run-down control is provided for simplified, safe operation of the pumping system. A simplified method of presenting pumping system performance and a design analysis procedure for matching of mechanical pumps to the boosters are described.

ISSN:0022-5355    

DOI:10.1116/1.1316687

出版商:American Vacuum Society    

年代:1972

数据来源: AIP

摘要:

Switching and memory effects can be observed in many metal–insulator–metal structures. These phenomena are generally explained in terms of filamentary conduction through the insulator. The nonhomogeneous conduction causes a nonuniform potential in the top metal electrode. These small potential differences are detected with the aid of a scanning electron microscope. A special ac detection scheme is employed to improve the normal voltage contrast obtained in secondary electron micrographs. A fixed frequency ac bias is applied to the device and the secondary electron detector is narrowly tuned to this same frequency. This technique allows the suppression of normal topographical and compositional contrast and significantly improves the signal-to-noise ratio for voltage contrast. The presence of current filaments inNb–Nb2O5–NiCrdevices is experimentally verified.

ISSN:0022-5355    

DOI:10.1116/1.1316688

出版商:American Vacuum Society    

年代:1972

数据来源: AIP