Thin oxide films such as YBa₂Cu₃O_7-x (YBCO), SrBi₂Ta₂O₉ (SBT) and ZrO₂ can be fabricated via physical vapor-deposition methods in a background of ambient oxygen, typically at a pressure of 5x10-4 Torr or greater, which prevents the use of most surface analytical methods during film growth. We have developed Mass spectroscopy of Recoiled Ions (MSRI) as a means of determining the elemental composition and structure of the uppermost 2-3 atomic layers under the ambient oxygen background required for the growth of single and multicomponent thin oxide films. By comparing the time evolution of the signals corresponding to the substrate and film during growth, it is possible to determine whether growth occurs via the Frank van der Merwe or Volmer-Weber process. In general, it is found that for relatively refractory materials such as ZrO₂, initial growth occurs via the Volmer-Weber process. For films which contain a relatively volatile component such as YBCO and SBT, 2-dimensional growth occurs at room temperature, but, at the temperatures required for crystallization, oxygen is necessary to stabilize the volatile film components, and growth occurs via the Volmer-Weber mechanism. The local density of electronic states at the surface gives rise in general to a "fingerprint analysis" which can be used to determine the chemical phase of a growing film. This method is used to study the effect of substrate temperature and oxygen partial pressure on the surface composition and chemical phase of these oxides.

*Work supported by the US Dept. of Energy, Office of Basic Energy Sciences under contract W-31-109-ENG-38, and by the Office of Naval Research under contract 852E1.

C60 thin films grown on metal substrates have attracted great interest in the past as they show peculiar electronic and chemical properties.

In this study, we present recent results on the growth of C60 films on Ag(001),Ag(110) and Cu(110) obtained by a variable temperature UHV-STM .

At low temperature, the C60 molecules nucleate on terraces, forming hexagonal islands. Increasing T, the nucleation takes place preferentially at descending steps and in a second time large islands are created. After high temperature annealing, peculiar quasi-periodic structures are observed, in which some molecules appear brighten than the surrounding ones. This effect is not due to a surface reconstruction, but to the large charge transfer from the metal surface. Second layer islands show a different arrangement.

The STM results will be related with recent observations obtained at the synchrotron radiation facility ELETTRA (Italy) on the same systems.

When a thin film is deposited on a cantilever, residual stresses due to thermal expansion and lattice parameter mismatches lead to deflection of the beam. This response has been used as the basis for measuring residual stress, and the product of biaxial modulus and expansion coefficient differential. Typical application restricted to thick substrates has the advantage of yielding information independent of substrate properties, but has two disadvantages. One is that it does not yield values for modulus and expansion coefficient separately. The second is that for film-substrate combinations of interest, the deflection of the beam may be small, limiting the accuracy of the results. For substrates of known properties, varying finite ratios of thicknesses permits measuring both modulus and expansion coefficient. Thinner ubstrates can provide increased deflection and improved accuracy. Micron and sub-micron cantilevers have been fabricated at OGI from thin single crystal Si machined using a focused ion beam milling workstation. Si cantilevers had essentially zero deflection prior to film deposition. Micron thick Al films were deposited on a number of cantilevers. Beam lengths were in the range of 15 to 20 microns.

Film/substrate thickness ratios varied from smaller than one to equal to more than double. Deflections were measured as functions of distance along the lengths of the beams. It has been demonstrated that micro-cantilevers can be made with reproducible geometries and comparable film and substrate thicknesses, so as to produce deflections suitable for accurate measurement and independent determination of separate physical properties.

The nature and quantity of the organic compounds significantly influend not only the adsorption potential of the SiC particles and their incorporation rate, but also the nickel-phosphorus electrocrystallization and electrodeposition mechanism.

It was found, that the most appropriate additives for Ni-P composite coatings are nitrogenous organic compounds, which weakly inhibit the cathodic process and their influence is mainly determined by their interaction with the particles. In this respect, the best suited additives are amino compounds containing Si atoms in their molecules (I.e. silane). Anion active additive, saccharin unlike these additives is non-stimulator and in fact inhibitis SiC particles codeposition. The different action is the result of loose adsorption of these molecules on the SiC surface and their brightening effect, which decreases the particle capture in Ni-P deposit.

Thin films of kanthal were deposited onto clean glass plates and ceramic substrates by flash evaporation in a vacuum of 3X10^-5 torr. The in-situ resistance of as-grown films measured at various temperatures revealed that these films were stable at high temperatures and had negligible temperature coefficient of resistance. The thickness dependence of conductivity was also measured and it was observed that it obeyed Fuch-Sondheimer theory of electrical conduction of metallic films. The surface resistivity of these films was estimated from the ac conductivity measurements carried out using an LCR meter.

One of the important applications of kanthal films is as a microwave absorber in Coupled-Cavity Traveling-Wave Tubes. To characterize these films for their microwave absorption behavior Kanthal films of various thicknesses were coated onto the walls of a Ku-Band cavity and the transmission loss of the cavity was measured at 17 GHz. The skin depth of the film (which is different from that of bulk material) has been estimated in the light of the measured values of the dc and ac conductivities of the films and a theoretical explanation for the observed thickness dependence of microwave loss has been presented.