ZrO2 films were deposited on 12×17×0.5mm Si(100) single-crystal substrates or 9×18×0.5mm glass substrates using plasma-enhanced metal organic chemical vapor deposition (PE-MOCVD) with Zr (DPM) and oxygen as reactants. A mode converter was used to generate the plasma. The mode converter changes the microwave mode from TE10 (rectangular) to TM01 (circular), rising plasma density. We anticipated that ZrO2 film would be deposited at a lower temperature. The film obtained at 500°C was polycrystalline, but a predominantly (111)-orientated film was obtained at 300°C. Similar results were obtained on Si and glass substrates. No impurity such as hydrocarbon or carbon was detected in films. ZrO2 films had a tetragonal phase with lattice parameters of a=b=0.507nm and c=0.518nm. ZrO2 films deposited at 300°C at different microwave powers exhibited the same X-ray diffraction patterns. Film orientation was independent of microwave power. Film deposited for one hour at 300°C was 90nm thick with 30nm roughness and a refractive index of 2.10. Film growth activation energy was 14.5kJ/mol. We concluded that plasma generated by converting microwave to TM01 mode deposited preferred (111)-oriented ZrO2 film at a low temperature of 300°C.
We attempted to increase resistivity (ρ) while maintaing good soft magnetic properties by using industrial-grade permalloy (Ni80Fe20) as a core material. We added diethylenetriamine (DET) as an organic additive to NiFe bath to increase resistivity. The adding of 3∼4ppm of DET produced a film with resistivity three times resistivity as high as Ni80Fe20, and the higher resistivity film retained the good soft magnetic properties due to the codeposition of small amounts of carbon and sulfur. Increased resistivity was caused because the resulting microstructure contained more minute crystal grains than the conventional microstructure. The higher resistivity NiFe film exhibits higher permeability than that of conventional Ni80Fe20 film above 30MHz because eddy current loss is suppresed.
We studied cyanide-free autocatalytic electroless gold plating baths using sodium gold sulfite and found that gold was autocatalytically deposited when sodium thiocyanate or sodium iodide was added to the sodium gold sulfite solution. We began by studying the effect of pH, additional sodium thiocyanate, gold concentration, and bath temperature on the deposition rate in the bath to which sodium thiocyanate was added. The pH and gold concentration had more pronounced effect than the other parameters studied. Lowering pH increased the deposition rate and increasing the gold concentration proportionally increased the deposition rate. This bath yielded a smooth lemon-yellow gold deposit of 1.28μm at a deposition rate of 0.43μm/h. Gold was provided also autocatalytically deposited by adding sodium iodide. Using this bath, we studied the effect of gold concentration, pH, and the addition of sodium sulfite or sodium iodide on the deposition rate. The gold concentration and the pH had more pronounced effect than the other parameters studied, same as in the case of the bath containing sodium thiocyanate. But the deposit from sodium iodide bath was reddish and rough, then some additional agents were examined. Addition of nicotinic acid and polyethyleneimine gave smoother deposit. In sodium iodide bath, about 1μm/h of deposition rate was given, but according as increase of the plating thickness, growth of dendrite crystal was observed. As for this bath, continuous use more than 1M. T. O. was possible.
Colloidal silica-dispersed IrO2 films were formed on a titanium substrate by thermal decomposition and examined by depth profiling with a scanning electron microscope and electron probe microanalyzer. Catalyst films consisted of triplex layers with an iridium oxide-enriched outside, a silica-enriched inside, and an intermediate section where the two oxides interpenetrated. Colloidal silica supplied at the surface of films thus moves easily through the layers inward to form further silica-enriched layers. In other words, silica gradient concentrations are built into films; such gradient concentrations appear to give anode films their long service life.
We used X-ray diffraction to study the effects of cobalt and nickel on electrodeposited iron-tungsten-based alloy film amorphization. The minimum tungsten content required for amorphization decreased from ca 13at% in iron-tungsten binary alloys to ca 4at% or ca 7at% in ternary alloys with cobalt or nickel. A ternary alloy structure with a tungsten content less than that required for amorphization tends to be influenced by the substrate surface structure and to be stable only at low temperature. This appears to be why ternary alloys with cobalt or nickel with lower tungsten content become amorphous than iron-tungsten binary alloy.
Bodily exposure to ultraviolet (UV) ray irradiaction has drawn increased attention, particularly in its relationship to skin cancer. UV shielding materials has thus been widely studied. We investigated the how to prepare TiO2 particles as UVA shielding. By adjusting the seed amount during hydrolysis, we prepared a technique for anatase TiO2 powders whose transmittancy curve in the UVA and UVB regions is almost the same as that of commercially available rutile TiO2. Anatase TiO2 powders exhibited superior UV shielding. We experimentally reified the appropriateness of the simulation proposed by Stamatakis et al. for suitable-size particle, demonstrating the satisfactory coincidence of UVA shielding with minimum percent-transmission micell. Generally, TiO2 powders superior for UVA shielding shows poor transparency over the visible wavelength range. Excessive grinding of powders lowered UV shielding, while slightly imposing visible transparency range.
Thermal oxidation behavior of aluminum-ion-implanted titanium nitride films has been studied in dry oxygen atmospheres. TiN films about 2μm thick were prepared on austenitic stainless steel AISI304 substrates using hollow cathode discharge ion plating. Al ions were implanted at 50keV and doses of 1×1017 and 3×1017ions/cm2. Continuous oxidation-weight-gain tests on TiN films implanted with Al, the structure of the oxide layers characterized by X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) used to analyze the chemical bonding states of elements in surface layers were used to evaluate samples. As-deposited TiN films were oxidized at above 873K and had rutile TiO2 near the surface. The oxidation rate of Al-implanted TiN films slowed in initial oxidation. The Al2p XPS spectrum of TiN film implanted with 3×1017Al/cm2 and oxidized at 1073K for 2 hours revealed Al2O3 at the surface, although no oxides were found in XRD patterns. Al oxides formed on the Al-implanted TiN films are considered to inhibit the film oxidation. Oxidation in Al-implanted TiN films resembles that in TiAlN films.
The cyanide-free silver plating bath that we developed produced good silver film, but the cell voltage of the bath increased over time if electrodeposition was conducted continuously. Green film also formed on the silver anode with increasing voltage. To clarify these phenomena, we studied the anodic polarization behavior of the silver electrode in the cyanide-free bath. The X-ray diffraction pattern for the green film agreed with that of AgI. Anodic polarization curves for the silver electrode indicated that less-conductive film formed on the electrode when the potential exceeded-0.3V. The polarization curve limiting current was increased by agitating the bath or increasing KI concentration. These results iudicate that Ag was dissolved into the solution via AgI rather than dissolving directly into the bath.