Papers by Keyword: Amorphous Oxide

Abstract: With the widespread use of film transistors, amorphous oxide thin films have excellent transparency and conductivity, stable performance, smooth and smooth surface, easy to etch and large-area preparation, are compatible with existing processes, and do not require subsequent annealing to simplify the process. Process and other advantages have been applied to many fields such as thin film transistors. The principle of the amorphous oxide is basically the same as that of the crystalline state, Magnetron sputtering technology can prepare super-hard films, corrosion-resistant friction films, superconducting films, magnetic films, optical films, and various films with special functions. It is widely used in the field of industrial film preparation. This article focuses on the principle and characteristics of magnetron sputtering technology for electronic materials, the development history of magnetron sputtering technology and its development trend.

Abstract: Titanium oxide (Ti-O) films were prepared by low-voltage (i.e., 5-15 V) anodization of titanium plate in different hydrochloric acid (HCl) concentrations. Phase composition and surface microstructure of the anodized sample were investigated through XRD and SEM characterizations. Samples anodized at 15 V and in 0.6, 1.5 and 3.0 M HCl concentrations show higher amount of crystalline TiO₂ (i.e., anatase and rutile) phases as compared to other anodizing conditions. The three samples show open pores microstructure on the anodized surface. Samples anodized at lower voltages and in low to medium HCl concentrations also produce loosely bonded amorphous Ti-O granules on top of the crystalline TiO₂ phases. After annealing these samples at 400 or 600°C in air, further oxidation occurred on the anodized surface particularly at pores, contribution to slight increase in the crystalline phase. It suspected that the presence of amorphous Ti-O granules on top of crystalline TiO₂ phases at initial anodizing stage, hindered movement of OH^- and Cl^- anions onto the anodized surface, thus inhibited further growth of the crystalline TiO₂ phases.

Abstract: Formation behavior of nanovoids during the annealing of amorphous Al₂O₃ and WO₃ was studied by transmission electron microscopy. The density and size of the voids in Al₂O₃ and WO₃ increase with increasing annealing temperature from 973 to 1123 K and from 573 to 673 K, respectively. It is suggested that the formation of nanovoids during annealing is attributed to the large difference in density between as-deposited amorphous and crystalline oxides.

Abstract: Thermogravimetry was used to study the oxidation behaviour of a lamellar Ti46Al8Nb alloy during holding at 700°C in synthetic air. A parabolic plot of the oxidation kinetics shows three different regimes over the total duration (50 h) of the tests corresponding to decreasing values of the parabolic rate constant. The oxide scale was characterized by glancing-angle X-Ray diffraction and transmission electron microscopy. The scale was found to be bi-layered with an outer part that consists of amorphous aluminium rich oxide whilst the inner layer is made of very small cristalites of titania distributed in the same amorphous oxide.

Abstract: The following nanocrystalline binary oxide systems were studied: Mg-Ti, Ni-Ti, Zr-Al, as well as some pure and doped unary oxides. The xerogels were heated at a constant T (200 to 1600°C) for 3 to 6 hours. There was a threshold tempearture for oxide formation and in many cases the products were metastable nanocrystalline phases, depending on the grain size and composition, including doping. The oxide phases of Ni-Ti, Mg-Ti, and Zr-Al, formed at 900 °C are different from those formed at higher temperature. New ranges of solid solutions and the formations of higher temperature structures were found. A transition phase can be defined as a structure formed at relative low tempearture, irreversibly transforming at higher temperature into an equilibrium phase of the same elemental composition. Some low temperature transition phases have a structure similar to that of a high temperature equilibrium phase, e.g., (the equilibrium phase is given in parentheses) tetragonal ZrO2 (monoclinic) and low-T qandilite-like solid solutions (qandilite + geikielite). Others are unique with no representation in the equilibrium phase diagram, e.g., gamma-like alumina (corundum) and anatase (rutile), which are formed as nanocrystalline oxides due to a low growth rate caused either by a low temperature of calcination or due to additives. To asses the importance of crystal size in the stabilization of transition phases, the following studies were undertaken: (a) XRPD analysis of all unary, doped and binary compositions; (b) the evolution of transition phases in HT XRPD of the Mg titanates; (c) the phase evolution was studied with time at temperatures were mixtures of transition and equilibrium phases were found; (d) the retention of pure tetragonal ZrO2 on quenching Al-Zr oxides after calcinations at high tempetature; (e) additional evidence from HRTEM, SEM and DTA experiments was also collected. A model, correlating the size effect with the unusual phases and structures is proposed.

Abstract: The single crystal of Si is still one of the most important candidates among other materials including Single crystals of SiC, GaN, C(diamond) or compound semiconductors. The innovative process as called CMG(Chemo-Mechanical-Grinding) for Si wafer has been recently developed which is different from conventional CMP(Chemo-Mechanical-Polishing ) process. The CMG process can be done under dry conditions using CeO2 based solid bulk abrasives. The microstructures for surface and subsurface of Si single crystal after CMG process were analyzed using TEM/EDX, AFM, MFP-3D Microscope. The mechanism of CMG process was also investigated by X-ray diffraction and ICP chemical analysis using products by chemical reaction between Si and CeO2 abrasives. The results showed that Si single crystal after CMG had, 1) no defects even Si lattice revel or mechanical imperfections,2) better surface roughness as compared to CMP process. The CMG mechanism concluded that CeO2 reacted with Si producing Ce-Si-O amorphous phase.