1510.Preparation and investigation of (BaSr)TiO3 thin films

1510.Preparation and investigation of (BaSr)TiO3 thin films

Classified abstracts 1507-1517 mass spectrometer. The experimental energy spectra for sputtered neutral atoms are compared with the energy spectra of ...

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Classified abstracts 1507-1517 mass spectrometer. The experimental energy spectra for sputtered neutral atoms are compared with the energy spectra of the ion component. It is shown that the experimental data are not consistent with the kinetic ion emission mechanism but are in accordance with another mechanism determined by the nonadiabatic nature of motion of the sputtered particle with respect to the target surface. V I Veksler and B A Tsipinyuk, Zh Eksper Teor Fiz, 60 (4), April 1971, 1393-1398 (in Russian). 30 1507. Influence of composition of gas phase on growth and properties of epitaxial films of gallium arsenide. (USSR) Influence of the proportions of G a and As in the gas phase on the growth rate and morphology of epitaxial GaAs films is investigated. The maximum growth rate is obtained at the relation of G a to As of 0.8 to 1.5. The most perfect films are obtained at stoichiometric composition of gas phase. N N Bakin et al, Proc Rost KristalPlen Polup, Novosibirsk 1970, 163169 (in Russian). 3O 1508. Structure and some properties of single crystal films of cadmium sulphide and selenide obtained in isothermal regime. (USSR) The technique of growth of single crystal films of CdS and CdSe on mica, sapphire and ruby in vacuum, under conditions close to isothermal, is presented. I P Kalinkin et ai, Proc Rost Kryst Plen Polup, Novosibirsk 1970, 666673 (in Russian). 30 1509. Growth mechanism of epitaxial films of cadmium sulphide and selenide in different technological processes. (USSR) The morphology of mechanically polished (0001) and (0001) planes of CdS and CdSe was investigated in dependence on evaporation temperature. The evaporation experiments were carried out in vacuum at 5 × 10-e torr at 500 to 750°C. It is shown that evaporation of cadmium sulphide and selenide in vacuum proceeds according to two different mechanisms depending on temperature. At lower temperatures evaporation proceeds at uniform removal from the single crystal surface of layer after layer while maintaining the original orientation. Defect-hollows are filled and defect projections are evaporated. At higher temperatures the evaporation is determined by the high energy of evaporating particles exceeding the bond energy in the crystal lattice. Migration of atoms over the surface does not exist, which results in the development of defects on surface. It is observed that, to select conditions for film deposition of easily volatile materials, it is advantageous to determine conditions of thermal evaporation of the single crystal faces, whose orientation is required in the deposited film. A V Vanyukov et al, Proc Rost Krystal Plenok Polupr, Novosibirsk 1970, 192 200 (in Russian). 30 1510. Preparation and investigation of (BaSr)TiO3 thin films. (USSR) (BaSr)TiO3 thin films were prepared by vacuum condensation of the crushed ceramics prepared by twofold firing. To obtain stoichiometric thin films, the method of discrete evaporation with a mechanical vibrator was employed. The material was condensed on quartz substrates at 850°C in vacuum at 5 × 10-8 torT with a deposition rate of 5 A/sec. The degree of structural ordering of these films was investigated. Yu Ya Tomashpolskiy et al, Neorg Mater, 6 (7), 1970, 1366-1367 (in

Russian). 30 1511. Preparation and properties of thin films of multieomponent vitreous semiconductors. (USSR) Technique of shock evaporation was used to obtain thin films of vitreous semiconductors of the system As-Se-TI. V M Lyubin and G A Fedorova, Neorg Mater, 6 (10), 1970, 1891-1892

(in Russian). 30 1512. Electron-microscopic investigations of GeO film structure. (USSR) To determine the optimum conditions for vacuum evaporation o f germanium monoxide films, the structure of evaporated films is investigated with the aid of an electron microscope. Crystalline clusters of GeO are observed in the initial stages of deposition. The quality of the clusters in films evaporated on the same substrate is similar and does not depend on the evaporation conditions. Two forms of crystallites are observed: plates and needles. With increasing 620

film thickness, the evaporation conditions play an increasingly important role. At film thickness of 1 to 2/~m, the crystalline phase is observed at the deposition rate of 5 A/sec. At evaporation rates above 20 A/sec the films have amorphous structure. Annealing of the films in vacuum results in the transformation of GeO from the amorphous phase to the crystalline at 450°C. Below 350°C, the amorphous phase is stable. GeO changes its structure in moist atmosphere. Yu G Sakharov et al, Neorg Mater, 6 (10), 1970, 1821-1823 (in

Russian). 30 1513. Photoelectric properties of CdSxSel-x epitaxial films. (USSR) Single crystal CdSxSel-x films have been prepared and their photoelectric and electric properties investigated. The photosensitive films of solid solutions of CdSxSe~-x with x ranging from 0.1 to 1 and thickness of 5 to 20/~m have been prepared by deposition from molecular beams in vacuum at 5 × 10 5 tort. The single crystal films have a photocurrent maximum in the region of 510 to 720 nm and their basic photoelectric and electric properties are not significantly different from those of bulk single crystals. N V Gavrilenko et al, Neorg Mater, 6 (10), 1970, 1787-1791 (in

Russian). 30 1514. Mechanism of phase composition anomalies in CdS eondensates. (USSR) Mechanism of formation of thin condensed CdS films is investigated. The CdS films were evaporated from a graphite crucible at 10 -5 torr on to glass substrates or polystyrol foil at 60 to 80°C. Temperature of the evaporator ranged from 600 to 750°C. It is found that, in deposition onto amorphous substrates, the condensate is not formed immediately, but after a latent period, the duration of which is determined by the condensation rate. A critical deposition rate exists, equal to 7.4 A/see for CdS, which corresponds to a critical density of two-dimensional vapour, below which condensation does not occur even after prolonged supply of material to the substrate. In the case of CdS condensation on substrates with a preliminary deposited CdS layer or arbitrary metal, the latent period of condensate formation vanishes. In the initial stages of deposition the condensate consists of two phases c~-CdS and Cd, the formation of which is a result of thermal dissociation of CdS on evaporation in vacuum. As the thickness of the condensate increases, a mixture of hexagonal and cubic CdS or only hexagonal CdS are formed. L S Palatnik and M N Naboka, Neorg Mater, 6 (10), 1970, 1779-1783

(in Russian). 30 1515. Ageing of ultrathin films obtained by condensation of tantalum and iridium vapours in vacuum. (USSR) Irreversible changes in electrical resistance of ultrathin metal films, as a result of ageing in vacuum immediately after their deposition, are investigated. Films 10 to 50/~ thick were prepared by condensation of tantalum and iridium vapours in an apparatus equipped with a liquid nitrogen trap at pressure of 5 × 10-6 torr. Tantalum and iridium were evaporated by electron beam at a deposition rate of 0.1 to 0.3 A/see. Polished plates of amorphous quartz were used as substrates. Ageing in vacuum was performed at condensation temperatures of 250 and 450°C. It is found that iridium films have a crystalline structure characteristic of bulk metal. Tantalum films have face-centered cubic lattice with period characteristic of TaO. It is found that the electrical resistance of all ultrathin films obeys an exponential dependence on time. The ageing characteristics are explained by the occurrence of two diffusion processes. The first process is determined by activated migration of clusters on the substrate and their coagulation. If the film temperature is sufficiently high then diffusion changes in the cluster formations take place. V A Kholmyanskiy, Neorg Mater, 7 (5), 1971, 721-725 (in Russian). 30 1516. Investigation of the process of growth of CdS epitaxial films in an open gas-transport system. (USSR) Thermodynamic calculations of partial pressures of the components of the gas phase in an open gas-transport system during evaporation of CdS in hydrogen are performed. The mass transport rate is experimentally investigated. I M Kotelyanskiy, Neorg Mater, 7 (6), 1971, 925-929 (in Russian). 3O 1517. Utilization of ion beams and high-frequency discharge for the deposition of dielectric and metal films. (USSR) Utilization of a high-frequency ion source with a vapour source for