We propose a phenomenological model which describes the ferroelectric film formation on the oxide substrate and its dielectric, optical and mechanical behavior. The model delineates the stability regions of different ferroelectric domains¹ formed during the deposition process and shows their relation with the superstructure imposed to the film by the substrate. The approach contains detailed crystallographic analysis and thermodynamic consideration including thermo-electro-mechanical coupling. It also takes into account the epitaxial relationship between the film and the substrate, the mechanical boundary conditions and the surface morphology. Calculated theoretical phase diagram shows the predominance regions of the structures with different polarization orientation with respect to the substrate surface. The model is applied to the case of the epitaxial PbTiO₃ thin films which are grown on the MgO(100) single-crystal substrate. A numerical modeling of the stress level in the film is performed. Its influence on the dielectric and optical properties is discussed.

¹B.S. Kwak and al, Physical Review B, 49, 21, (1994) 14865

Transparent conductive thin films have been studied by many research workers because of their wide industrial applications. In recent years, the application of these thin films can be summarized into optical transparent electrodes in display devices, photovoltaic cells, and other opto-electronic devices. Many new materials and various manufacturing techniques have been developed to satisfy technological requirements.

The most widely used materials for the transparent electrodes are semiconducting oxides such as zinc oxide(ZO), tin oxide(TO), and indium tin oxide(ITO). Among these transparent oxides, ITO has the highest electrical conductivity and optical transparency.

The development trends for ITO coating techniques can be integrated into the decrease of operation temperature to use various materials as the substrates. ITO has been produced by a number of techniques such as DC (or rf)- sputtering, chemical vapor depositionCVD, evaporation, etc. In particular, ion beam assisted electron beam evaporationIBAE technique offer room temperature operation in addition to the flexibility in controlling film properties. In this IBAE technique, the establishment of the deposition parameters such as the flux and energy of oxygen ion beam, incident angle of the ion beam, ITO/O₂ flux ratio, etc. is very important to obtain optimal ITO film at the room temperature.

In this study, the effects of the deposition parameters such as the flux and energy of oxygen ion beam, incident angle of the ion beam, and evaporated ITO/O₂ ion beam flux ratio on the physical, optical, and electrical properties of ITO films deposited on the plastic substrates at the room temperature were investigated.

The originally designed low-pressure RF plasma-chemical reactor with hollow-cathode supersonic plasma jet system (RPJ) has been used for deposition of polycrystalline copper nitride thin films.

From comparison of experimental values of chemical composition with the theoretical ones and from XRD analysis of the samples, which have been made at the RF power absorbed inside the RPJ reactor below approx. 75 W follows that the stoichiometric Cu₃N films have been achieved. The typical value of the deposition growthrate was found in the order of 16 nm/min for RF power P_w = 40W. The optical energy gap E_g and microhardness H of the deposited Cu₃N thin films increase with decrease of RF power. There are E_g=1.24 eV and approx. H=8.8 GPa for the sample deposited by RF power 40 W. For deposition RF power higher than approx. > 75W it appears that a small amount of Cu microparticles is diluted in the Cu₃N film.

The relative high stability of Cu₃N thin films which has been found for different environmental conditions together with relative high hardness indicate that the Cu₃N thin films can be used not only in microelectronics for write-once optical recordingmedia, but for some application in the surfaces treatment technology, too. Especially the modificated RPJ with multi-jets system enables the deposition of Cu₃N thin films onto internal walls of cavities, holes and on surface of complex shapes of hollow substrates.