NANOSCALE METAL FILM ELECTRONICS
Authors:   Lviv National Ivan Franko University, Ukraine, Bihun Roman , Koman Bohdan ,   Lviv National Ivan Franko University, Ukraine
Published: April 2024

The purpose of work is the development of technique for the deposition of nanoscale metal condensates of fine-crystalline structure of Au, Ag, Cu and transition (Mn, Hi, Pd and Cr) metals on the surface of amorphous glass or carbon substrate, and such surfaces pre-coated with wetting weakly conductive underlayers of Ge, Sb or Si, with mass thicknesses up to 8 nm.With predicted, controlled structure and electrophysical properties of metal films by use the combination of "quench deposition" technology and wetting underlayers with subsequent thermal stabilization in the interval of the first temperature zone of the modified Movchan-Demchyshyn Zone model. Practicalimplication. To analyze theoretical approaches for quantitative prediction of size charge transport phenomena in classical and ballistic regimes and the impact of surface inhomogeneities on them. Experimentally study the physical regularities of dimensional effect impact on the structure, electrophysical and optical properties of nanoscale condensates of the studied metals. The goal tasks must be solved: Develop a method of controlled metal films deposition with given physical parameters. Investigate fine-crystalline metal films with a given structure and establish criteria for the selection of wetting underlayers. To experimentally investigate the size dependence of the average linear sizes of crystallites D in the studied metal films to predict the features of the structure, surface morphology, and patterns of change in the dc percolation thickness in metal condensates. To study the regularities of condensate formation with given average linear dimensions of crystallites depending on the nature of the material, the thickness of the wetting underlayer and the mode of thermostabilization of their properties.Methodology. Nanoscale metal condensates (films) were depositeded with method of "frozen condensation" (quench deposition) of condensation of vapor thermally evaporated at ultra-high vacuum (pressure of residual gases did not exceed 10-7Pa) of metal on an amorphous glass substrate or substrate cooled to 78-90K,pre-covered with wetting Ge, Sb or Si underlayer of given mass thickness. The thickness of investigated films was monitired by shift of the resonant frequency of quartz vibrator. Electrical and thermoelectric power studies of the films consisted in studying ofsize dependence of their kinetic coefficients. Films resistance of correct geometric shape samples were measured by two-probe method, thermoelectric powerwith compensation method. Structure of studied films was monitored with transmission electronography and electron microscopy. The morphology of film surface was studied by scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The listed approaches were performed by complementary and mutually controlled experimental and theoretical approaches. Metal films mechanical tensiones grown by thermovacuum evaporation methodin VUP-5A chamber undervacuum not worse than 10-5Pa were studied. Chemically polished surfaces of single-crystal silicon plates of KEF – 4.5 (111) were used for metal film mechanical tensiones investigation. Residual mechanical tensiones of the substrates caused by their mechanical processing were removed by annealing in vacuum at temperature ~ 1000°С (±1°С). After the final etching in the polishing herbator SR-4, Si-substrates were cutby dimensions of 70 × 4 × 0.25mm3. Practicalimplication. Experimentalinvestigation are necessary for the development of methods of controlled nanosized layers deposition of more refractory metals (in particular, Ta, Re, Hf and others), which is promising for use in modern micro- and nanoelectronic technology. Value/originality. The complex technique of controlled deposition of nanoscale metal films with a predetermined structure and predicted electrophysical and optical properties in a wide range of thicknesses has been created. Metal films preparing process with specified average linear grain sizes was achieved by use the methods of "frozen condensation" and weakly conductive wetting underlayers substances that prevent coalescence of metal nuclei and selection of temperature stabilization mode at temperatures close to the upper limit of the first temperature zone of Movchan-Demchyshyn Zone model.