Growth and optical properties of transition metal oxides single crystal solid solutions
Abstract NiO, CoO, MnO single crystals and single crystal solid solutions of Ni c Mg 1− c O, Co c Mg 1− c O and Mn c Mg 1− c O were grown by the method of chemical transport reaction (the “sandwich” technique). The nature of the observed absorption and luminescence bands is explained in terms of the electronic transition of bivalent nickel, cobalt and manganese. The fine structure of the observed bands in NiO and MnO are connected to the pure exciton transition and to the exciton-magnon excitation.
2D monocrystalline nanostructures of cobalt oxide Co3O4 for sensing individual molecules
In this work, the sensory properties of a thin film of a Co3O4 monocrystal 0.5 nm in thick with a (111) plane are studied on the example of alcohol molecules of methanol, ethanol, propanol, and butanol. The regularities in the interaction of alcohol molecules with film surface are investigated. The energy profiles of interaction are calculated and the values of activation energy are determined. It is established that the value of activation energy is determined by the weight of the adsorbed molecule and its configuration relative to the surface of cobalt oxide. The regularity of the change in the electrical resistance of the Co3O4 film during the adsorption of various alcohol molecules was revealed. It is found that the monocrystalline nanostructure of cobalt oxide Co3O4 is very promising as a sensory surface, which makes it possible to register individual molecules.
Bevel RIE application to reduce defectivity in copper BEOL processing
Bevel etch used during wafer fabrication for semiconductor devices is discussed. In this case, the bevel etch process was utilized in middle of the line processing (MOL) to reduce back end of line (BEOL) defectivity. Tungsten and titanium nitride films, from the formation of contacts to the transistors, extend into the bevel region of the wafer and have been shown to initiate arcing. This can spread foreign material defects on the front side of the wafer in various BEOL post processing steps including subsequent reactive ion etching, SEM metrology and film depositions. The bevel etch tool confines a plasma etch to the outer edge of the front side of the wafer (which can be individually adjusted) and can remove dielectric, organic and Ti/TiN/W films using a fluorine based chemistry.