摘要:

Two different pairs of x‐ray reflecting multilayer coatings have been tested in a double crystal monochromator configuration. The two pairs consisted of Ni (0.4 nm)–C (1.85 nm) and NiSi (0.4 nm)–C (1.85 nm), both with 225 periods. In order to determine the resolution in the energy range of 600–900 eV, the photoelectron yield of several 3dtransition metal compounds was recorded as well as the throughput around the NiLlines. We found for both pairs a resolving power of 220. Simulations taking into account the angular divergence of the x‐ray beam yield a resolution of 250. The difference with the observed value can be due to the nonhomogeneity of the multilayer coating.

ISSN:0734-2101    

DOI:10.1116/1.577185

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Polystyrene microshells filled with deuterium and tritium gas are important target shells for inertially confined fusion (ICF) and are particularly promising for targets containing spin–polarized hydrogens fuels. A currently active approach to the latter uses polarized D in HD, in a method which requires preservation of the high purity of the initially prepared HD (very low specified H2and D2concentrations). This would not be possible if dissociation should occur during permeation into the target shells. We have thus tested polystyrene shells using a novel method which employs very pure ortho‐D2as the test gas. An upper limit of 6×10−4was deduced for the dissociation probability of D2upon room temperature permeation through an approximately 8 μm wall of polystyrene, clearing the way for use of polystyrene target shells for ICF fusion experiments with spin–polarized hydrogen–isotope fuels.

ISSN:0734-2101    

DOI:10.1116/1.577186

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Two techniques for calibrating leaks, one primary and one secondary, are described. The ΔPΔVmethod, a primary technique, is a modification of thePΔVtechnique which requires less time, has smaller outgassing error, and allows simultaneous, automated calibrations of several leaks in the range 10−8–10−12mol s−1. The pressure difference method is a comparison technique in which a mass spectrometer is used to compare the partial pressure of gas collected from the leak being calibrated to a known partial pressure generated by a constant flow. It is useful for calibrations in the 10−12–10−15mol s−1range. Both methods have been incorporated in an automated apparatus.

ISSN:0734-2101    

DOI:10.1116/1.577187

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

In the present article, starting from microscopic viewpoint, a new theory of rarefied gas dynamics in the range of free molecular flow has been studied. In this theory, the matrix‐probability method Y. Wu,RarefiedGasDynamics, edited by L. Talbot (Academic, New York, 1961), p. 141; J. Vac. Sci. Instrum.42, 876 (1965) has been employed to calculate transmission probability and a three‐dimension dynamic model has been suggested which can satisfy any complicated boundary conditions theoretically. Finally, the reasons why the transmission probability of gas molecules through a moving channel tends to a constant value (which is smaller than 1) rather than unity while the drag speed increases infinitely have been explained.

ISSN:0734-2101    

DOI:10.1116/1.577188

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We have developed a new method to measure the temperature of substrates during thermal treatments at elevated temperatures. In this method the emissivity of the substrate is calibrated automatically. The accuracy of the method has been investigated systematically. This method has been used for theinsitumonitoring of substrate temperature during the sputter deposition of aluminum thin films. The temperature profiles during the depositions at various temperatures of the heating stage were examined.

ISSN:0734-2101    

DOI:10.1116/1.577138

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

ISSN:0734-2101    

DOI:10.1116/1.577139

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

ISSN:0734-2101    

DOI:10.1116/1.577140

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Significant improvements in the uniformity of epitaxial layers of GaAs, deposited using a V80‐H molecular beam epitaxy system, can be obtained by modifying the crucible so that the flux is directed towards the center of rotation of the substrate. This has been obtained with a dual crucible system, consisting of a tilted conical insert inside a large capacity straight sided crucible. With this combination the layer uniformity can be improved to better than ±1.5% over the useable area of a 76 mm diam substrate and to ±0.7% for 50 mm diam substrates. These results are in excellent agreement with the predictions of recent flux modeling calculations.

ISSN:0734-2101    

DOI:10.1116/1.577141

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Plasma processing in chambers located downstream from a source are gaining widespread use because they allow etching and deposition with minimal damage. This minimized damage, however, is achieved by using a low ion impact energy, which can lead to a poorer etch anisotropy. The best anisotropy for a given impact energy requires the lowest possible ion temperature. Laser‐induced fluorescence measurements show that room temperature ions can be attained using a multidipole‐confined discharge. In comparison, ion temperatures downstream from electron cyclotron resonance sources are much hotter, according to recent reports.

ISSN:0734-2101    

DOI:10.1116/1.577142

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

ISSN:0734-2101    

DOI:10.1116/1.577143

出版商:American Vacuum Society    

年代:1991

数据来源: AIP