摘要:

Photodesorption from an oxygen‐saturated silicon(100) surface was studied with photons of wavelength 250–1100 nm. The desorbing species were monitored with a mass spectrometer over the mass range of 2 (H2) to 44 (CO2). Only CO2was observed to desorb with a threshold value of ∼2.76 eV, and the desorbing signal was linearly dependent on the incident photon intensity. Perhaps most important, the photodesorption activity decreases markedly with the controlled decrease of surface impurity carbon content.

ISSN:0734-2101    

DOI:10.1116/1.572303

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

A quantitative LEED intensity analysis of the Ag{110}1×2–O structure is described. Thirteen structural models were tested with the conclusion that, while the model of oxygen atoms in the bridge sites within the ‘‘troughs’’ of the substrate surface is better than the others in approaching agreement with experiment, none of the models tested in this work is satisfactory. A set of experimental LEED intensity data is presented.

ISSN:0734-2101    

DOI:10.1116/1.572315

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

The characteristics of the surface of various stainless steels are reviewed. The property of these alloys that makes them stainless is the formation of Cr2O3on the surface. It has been found that this protective layer can be modified relatively easily by heating, abrading, chemical treatment, or ion bombardment. Modification can be changes in the chemical composition of the surface layer or the formation of a layer of segregated material on the surface. These changes may alter the protective nature of the surface films. The outgassing characteristics of stainless steel surfaces also vary depending upon the treatment these surfaces receive.

ISSN:0734-2101    

DOI:10.1116/1.572301

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

A Mössbauer depth profiling technique has been developed which provides depth selective information about composition, stoichiometry, chemical nature, and structure of iron oxide films. A depth resolution of 5 Å or better can be obtained. The method is especially useful for very thin oxide layers (<100 Å) where standard methods can give only very limited information. The method uses special thin film samples of metallic iron which contain a thin probe layer of57Fe, the rest being depleted of this isotope. Thus, the power of Mössbauer spectroscopy for the identification of iron compounds is combined with a high resolution nondestructive depth profiling technique. The method is applied to study the low temperature oxidation of iron films. By oxidation at 453 K in pure oxygen a nonstoichiometric or noncrystalline oxide is formed.

ISSN:0734-2101    

DOI:10.1116/1.572302

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Very hard diamondlike carbon films have been prepared with the aid of an ionized deposition technique. The growth mechanism of films deposited in the presence of methane gas is discussed. The properties of these carbon films are as follows: The concentration of hydrogen atoms contained in the films is almost negligible. Micro‐Vickers hardness changes depended largely on the deposition conditions, but some of the values obtained were larger than that of sapphire. The 111, 220, and 311 reflections can be observed clearly in the electron diffraction patterns. Moreover the crystal structure obtained from these rings is very close to that of diamond.

ISSN:0734-2101    

DOI:10.1116/1.572304

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Investigations are reported into the effect of 350 eV He+, Ar+and Xe+bombardment of PbTe. The studies were made on surfaces of thin films prepared by molecular beam deposition under UHV conditions. The modifications to the films were monitored by measurements of the films’ carrier transport properties. Bombardment‐induced areal densities of carriers (electrons) up to 6×1013cm−2with near‐bulk mobilities were observed for ion fluences up 1016ions/cm2. The results are discussed in terms of preferential sputtering of Te in combination with beam‐induced mixing. It is concluded that the induced damage is located very close to the film surface. Whereas in the case of Ar+and Xe+bombardment the altered layer appears to extend over a depth commensurate with the ion range, the results for He+bombardment suggest that only the very surface is depleted of Te. There is evidence that ion‐induced desorption of weakly bound surface species contributes significantly to the observed changes in the areal density of carriers.

ISSN:0734-2101    

DOI:10.1116/1.572306

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

TaN thin films prepared by reactive sputtering are applied to a resistive thermoconductive type of humidity sensor. The characteristics of the sensor are as follows: The humidity sensor with TaN thin films can measure up to the absolute humidity of about 70 g/m3in the case of the sensor heated up to 150 °C. In its response, the rise time is 10 s and the fall time is 55 s.

ISSN:0734-2101    

DOI:10.1116/1.572307

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

Monte Carlo simulations of the growth of evaporated films have been carried out under various assumptions affecting the type of growth. The corresponding curves of Auger signal from the film as a function of deposition time have been analyzed to extract values for the electron inelastic mean free path λ. A smoothness parameterCdefined as the fraction of the substrate covered after the deposition of 1 monolayer equivalent of atoms, is used to characterize the degree to which growth is layer by layer, i.e., one layer is complete before the next one begins. It has been found that values of λ correct to within 10% can be obtained for values ofCas low as 0.85; belowCvalues of 0.85 the results for λ become unreliable. It is shown that film formation may be made essentially layer by layer by a reasonable choice of the deposition flux density and the substrate temperature, provided that the system is one in which atoms can walk off terraces. It is also shown that elastic electron backscattering should not affect these calculations significantly.

ISSN:0734-2101    

DOI:10.1116/1.572308

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

A furnace was fabricated to crack phosphine in ultrahigh vacuum. Thermodynamic calculations showed that phosphine should dissociate into the phosphorus dimer to a high degree. Furnace materials were compared by construction of all‐tantalum and all‐quartz cartridges which slid into the furnace hot zone. Phosphine was found to react with tantalum, but not to any great extent with quartz. The effects of baffles, studied with the quartz cartridges, lowered the temperature at which the cracking efficiencies began to increase and increased cracking efficiencies. The temperature range studied was from 100 ° to 1170 °C.

ISSN:0734-2101    

DOI:10.1116/1.572309

出版商:American Vacuum Society    

年代:1983

数据来源: AIP

摘要:

This report describes the design and operation of a unique‐nozzle‐beam gold deposition source that operates for extended periods of time without reloading. The source puts out a narrow beam of gold typically in the order of 2‐1/2° included ‘‘cone’’ angle. Maximum deposition rates are in the order of 1600 Å/min at 2.5 in. ‘‘throw’’ distances.

ISSN:0734-2101    

DOI:10.1116/1.572310

出版商:American Vacuum Society    

年代:1983

数据来源: AIP