摘要:

Platinum silicides have been prepared by depositing Pt thin films under UHV and controlled impurity ambients. The interfaces and surfaces have been characterized by Rutherford backscattering spectroscopy, cross sectional TEM techniques and SEM. Clean depositions yielded planar interfaces whereas increasing oxygen contamination produced nonuniform interfaces and surfaces. No differences in interfacial and surface uniformity, reaction rates, and phase growth sequence were observed between samples cleaned with normal device processing steps and UHV sputter cleaned and annealed samples provided the Pt films were impurity free. The influence of interfacial oxides on silicide kinetics has also been determined.

ISSN:0022-5355    

DOI:10.1116/1.570475

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

The pulsed Gas Process (PGP) has been used to produce Al/AlxOyThe pulsed Gas Process (PGP) has been used to produce Al/AlxOylayered coatings on a cylindrical surface. Previous work1has shown that the yield strength and surface morphology of aluminum films deposited at normal incidence is quite sensitive to the spacing of the oxygen gas pulse. The mechanical testing data follow a Hall–Petch equation for the yield strength. This gives an ideal range of conditions for test on curved surfaces. Free standing aluminum foils on the order of 20–35 μm thick have been deposited using PGP variations on a rotating cylindrical substrate with varying angles of deposit. The results show porosity in the unpulsed material, and fully dense material in highly pulsed material deposited at ±60° or less settings. The fully dense material shows ductility and the yield strength is reduced by a factor of 0.84 over the predicted flat plate strength.

ISSN:0022-5355    

DOI:10.1116/1.570476

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

Epitaxial metastable InSb1‐xBixalloys with InBi concentrations up to 12 mol % and (GaSb)1−xGexalloys with compositions across the pseudobinary phase diagram have been grown on GaAs substrates by multitarget rf sputtering. The InSb1−xBixfilm weren‐type while the (GaSb)1−xGexfilms werep‐type. Polycrystalline films from both alloy systems grown on Corning 7059 glass substrates exhibited strong (220) preferred orientation with lattice constants obeying Vegard’s law. Annealing experiments showed that the InSb1−xBixfilms were metastable in two directions on the In–Sb–Bi ternary phase diagram—the solid solubility of tetragonal InBi in zinc blende structure InBi was increased by more than a factor of 4 and the width of the InSb–InBi pseudobinary ’’line compound’’ phase field was increased to ?0.5%. Both InSb1−xBixand (GaSb)1−xGexfilms were found to be stable to decomposition during long anneals which, in the case of InSb1−xBix, were within 100°C of the equilibrium liquidus temperature. Annealing studies carried out on (GaSb)0.38Ge0.62showed that such films transform from the as‐deposited (220) oriented alloy to GaSb–rich and Ge–rich phases in which the solute concentrations continuously decrease until an equilibrium two phase alloy is obtained. The activation energy for this process is 3.1 eV.

ISSN:0022-5355    

DOI:10.1116/1.570477

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

The pulse repetition frequency dependence of the delay time,td, in amorphous silicon films produced by electron‐beam evaporation in a Ti–Si–Ti sandwich structure has been found to give two opposite trends. Below about 1 kHz,tdincreases as the frequency is increased but is independent of the pulse duration. Above 1 kHz,tddecreases with frequency and is also reduced in magnitude by increasing the pulse width. In this paper, an electrothermal mechanism of switching has been used to explain the above phenomenon satisfactorily. The predictions of the model as regardstddecreasing with increasing over‐voltage and increasing film thickness, the threshold voltage exhibiting a half‐power law relationship with thickness and its temperature dependence, and the effect of space–charge injection around the electrodes are confirmed by experiments. Finally, a view of switching combining both thermal and electronic elements is presented.

ISSN:0022-5355    

DOI:10.1116/1.570478

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

The adsorption and condensation of Cu and Ag, up to several monolayers in thickness, onto Mo(100) has been observed at pressures below 2 ×10−10Torr in a study that used combined LEED, Auger, TDS, and work function measurements in a single experimental setup. The results show that Cu behaves similarly on Mo(100) and W(100) substrates, while some differences are found for Ag adsorption.

ISSN:0022-5355    

DOI:10.1116/1.570479

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

The use of low‐energy electron diffraction (LEED) for the quantitative determination of finite‐domain size effects in surfaces and for the separation of domain size effects and strain effects is demonstrated for the first time. Measurements are made of the angular distribution of intensity in diffracted beams observed in LEED from Ag (111) thin film grown epitaxially on mica. The broadening in these beams beyond that due to the finite instrumental resolution is analyzed in terms of three mechanisms limiting the long‐range order on the surface: steps, mosaic structure, and strain parallel to the surface. It is demonstrated that no steps exist, and that the considerable broadening that is present is due to mosaic structure rather than strain. The average size of this mosaic structure, as well as the average misorientation of domains, is determined.

ISSN:0022-5355    

DOI:10.1116/1.570481

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

The criteria for the formation of thin mixed valent films have been studied by depositing thin layers of Yb on an Al(100) substrate and carefully controlling the interdiffusion. X‐ray photoemission (XPS) of pure Yb surface layers shows only the divalent character of the filledf14shell. Formation of a mixed valent state begins when interdiffusion becomes substantial above 150°C. Further heating above 350°C causes the Yb to revert to the divalent state despite the fact that a charge transfer mechanism would predict the presence of a substantial trivalent component. It is clear that the divalent component is not predominant on the surface of our mixed valent film since low intensity ion sputtering converts the trivalent component to the divalent. Finally, we observe an increase in the divalent character of an alloy of stochiometry YbAl3at low temperatures smaller than that predicted by theory.

ISSN:0022-5355    

DOI:10.1116/1.570482

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.570483

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

Niobium films oxidized to thicknesses less than 30 Å by using different oxidation techniques (e.g. thermal, dc glow discharge, and rf glow discharge) were studied by XPS. Chemical shifts in the binding energies of Nb 3d(3/2) and Nb 3d(5/2) levels were used to identify the various oxides of Nb. Niobium films oxidized by thermal or dc glow discharge oxidation showed an outermost layer of Nb2O5. A pure Nb signal could be seen when the oxide films were thin. Suboxides could not be seen directly in XPS data. The composition of the oxide films produced by an rf glow discharge oxidation was found to depend on the rf peak to peak voltage and under certain conditions the XPS spectra clearly showed the existence of NbO. A discrepancy was observed between the oxide thicknesses estimated from the XPS data and the relative values of resistances of Nb–Nb oxide–Pb tunnel junctions fabricated by using these oxide films as barriers. The results are briefly discussed in terms of the difference in the oxidation processes and their importance in junction fabrication.

ISSN:0022-5355    

DOI:10.1116/1.570484

出版商:American Vacuum Society    

年代:1980

数据来源: AIP

摘要:

A nonplasma silicon dioxide etch process using anhydrous hydrogen fluoride at reduced pressures has been investigated. This technique involves the interaction of HF vapor with negative photoresist which catalizes subsequent etching beneath the photoresist. Etching in nonphotoresist coated areas can be eliminated by a shortinsituplasma pretreatment followed by HF etching at 190 °C, 10 Torr, and 500 sccm in a commercial etch system. Experimental details as well as a proposed reaction mechanism will be presented.

ISSN:0022-5355    

DOI:10.1116/1.570485

出版商:American Vacuum Society    

年代:1980

数据来源: AIP