Single Crystal Oxide Substrates Research Articles

Optical Characterization of Potassium Niobate Thin Film Planar Waveguides

AbstractInitial results of the waveguiding properties of KNbO3 thin films are presented. The refractive indices of epitaxial films deposited on single crystal magnesium oxide substrates have been measured. Additionally, these films have been used as the basis for modelling a potassium niobate thin film phase modulator. Results of the model are compared with existing technology.

Ultraviolet photoemission studies of molecular adsorption on oxide surfaces

This paper reviews the current status of ultraviolet photoemission (UPS) measurements of the interaction of molecules with the surfaces of metal oxides. A brief summary of the electronic, geometric and compositional properties of atomically clean oxide surfaces is given, followed by a survey of the various adsorbate/substrate systems that have been investigated by UPS. Essentially all of that work to date has been on single-crystal oxide substrates. A brief description is also given of the various theoretical methods that are being used to study molecule/oxide interactions.

An electron microscope study of thin ferrite films prepared by the oxidation of high purity vacuum-evaporated metal thin films

The oxidation of thin films of nickel, cobalt, iron, NiFe2 and CoFe2 has been investigated between 200 and 1200° C. The oxidation products for the elemental metals differ from the oxidation products observed in previous work upon bulk material. The oxidation mechanism proposed for bulk material is in general still valid in the thin film situation. Above oxidation temperatures of approximately 850° C both NiFe2 and CoFe2 form the respective ferrites, although in the case of nickel ferrite, traces of the γ-Fe2O3 tetragonal superstructure can still be detected at oxidation temperatures of 1200° C. Films of nickel ferrite and cobalt ferrite upon single-crystal magnesium oxide substrates, produced by oxidation of vacuum-deposited NiFe2 and CoFe2 thin films, have been investigated by transmission and scanning electron microscopy. It has been found that (100) nickel ferrite prepared by this technique grows epitaxially upon (100) magnesium oxide.

Single Crystal Silicon Epitaxy on Foreign Substrates

Single crystal silicon has been grown epitaxially on a number of single crystal oxide substrates by chemical vapor deposition techniques. Such growth has been obtained in large area single crystal form on α-alumina, spinel, and beryllia. The distinct orientation relationships between the silicon deposits and a multiplicity of crystallographic planes of the various insulating substrates are indicated. Compatible with the earlier observed growths of single crystal tungsten on α-alumina, a model which assumes a fit between the silicon and the metal ion sites in the oxide substrate can account for all the epitaxial geometries. A concept of multiple fits in the metal-oxide system in terms of integral lattice parameter values as a guide in substrate selection is suggested. Representative electronic properties of the films and model fabricated devices, as well as a measure of their consequence in microelectronics, are given.