The deposition of Pd ad-atom catalysts has been investigated through ICP-MS, CV, and EQCM measurement. Results indicate that Pd ad-atom catalysts are dispersed on the substrate at a Pd coverage <0.6. Pd catalysts are deposited like islands at a Pd coverage >0.6. Adsorption of anions and water molecules increases in proportion to the number of Pd atoms on the substrate. The relationship between the change in resonant frequency of the EQCM and the mass change for Pd catalysts is represented by Δm (ng cm-2)=-10.527Δf (Hz). Oxygen species are adsorbed in a more reversible manner by the dispersed Pd ad-atoms than by the Pd atoms shaped like islands. Results demonstrate that the profiles of CV and EQCM are highly dependent upon the dispersed state of the Pd atoms.
An electroplating bath for Ag-Co binary alloy films was developed and the surface morphology of deposited films from this bath was observed with an SEM. Ag-Co binary alloy electrodeposits that lacked impurity were fabricated from a bath containing AgI and CoSO4. The surface with Ag-Co electrodeposits was flattened by addtion of cresolsulfonic acid or by controll of the pH value. The composition of the Ag-Co alloy electrodeposits can be controlled by changing the current density. The deposited Ag-Co alloy films do not include other elements.
A study has been made of the luminescence during Ar-ion bombardment to Ce-implanted α-Al2O3. Ion implantation of Ce+-ions into α-Al2O3 was performed at an energy of 100keV with doses ranging from 5×1013 to 1×1016 Ce/cm2 close to room temperature. After ion implantation, the implanted specimens were annealed in an argon gas atmosphere at 400, 600 and 1000°C for 1 hour. Luminescence spectra were measured during 100keV Ar+-ion bombardment of the specimens via a spectrometer with three optical filters, two diffraction gratings and a photomultiplier. The luminescence spectrum for a non-implanted specimen has peaks near 340, 390 and 420nm, which correspond to defects in the α-Al2O3 itself. The main peaks of the luminescence spectra emitted from Ce-implanted specimens also appear near 340, 390 and 420nm. The peak intensity at 340nm decreases as the dose increases. The peak intensities at 390 and 420nm increase at doses ranging from 5×1013 to 2×1014 Ce/cm2 and decrease over a dose of 2×1014 Ce/cm2. Annealing causes the peak intensity to increase. Comparing the luminescence spectra after annealing of non-implanted and implanted specimens, the peak intensity at 340nm is higher for non-implanted specimens than Ce-implanted ones. In contrast, peak intensities at 390 and 420nm are higher for Ce-implanted specimens than for non-implanted ones. From the results, it is considered that Ce-implantation effects of luminescence appear at peaks of 390 and 420nm.
A new boundary element method has been developed to simulate the electroplating of a silicon wafer with copper. In this method, the Laplace equation is solved with three-dimensional or axisymmetric elements by representing the complicated phenomena near the anode and cathode surfaces as polarization characteristics (PCs) and using the PCs as nonlinear boundary conditions. Prior to electroplating, sputtering is used to coat a silicon wafer with a Tantalum nitride (TaN) film. The electrical resistance of thin copper and TaN films on a silicon wafer is then taken into account. To make a uniform copper film, the anode (copper plate) is divided into several pieces, and optimization of the current supplied to each piece of the anode is performed through use of the Simplex method.