Surface deposits containing hydrated Sn(II) species are generated when substrates are immersed in stannous chloride solutions, and then rinsed in water. These deposits, after a later immersion in an aqueous solution of PdCl2 , are capable of activating electroless plating baths to produce a metal deposit on the substrate. The Sn(II) species, however, can readily be photo‐oxidized by exposure to ultraviolet light in air, yielding Sn(IV) and thereby destroying the latent catalytic surface. Thus, selective electroless metal deposits on a variety of substrates may be generated by exposure through an appropriate mask.

Measured limiting currents iL for the deposition of copper on a platinum rotated disk electrode (RDE) were used to calculate the diffusion coefficients of copper ions in high-purity aqueous copper sulfate and copper fluoborate electrolytes. The diffusion coefficient in a 0.100M CuSO4/1.0M H2SO4 electrolyte was found to be 5.23 -+-0.13 X 10 -6 cmf/sec, while the diffusion coefficient in a 0.072M Cu(BF4)2/1.0M HBF4 electrolyte was found to be 9.88 _ 0.05 • 10 -6 cm2/sec. The values of iL were found to be directly proportional to the square root of the disk rotational rate ~,, as predicted by theory. Consistent correlations between the kinetic parameters controlling copper depositions and the concentration of addition agents were found for copper fluoborate electrolytes containing Cubath Hy, z thiourea, and gelatin. Generally both the transfer coefficients (ar and the exchange current densities (io) were found to decrease with increasing concentrations of additives, in accord with the hypothesis that additives retard primary charge transfer and the rate of copper deposition. Anomalous results were obtained at a thiourea concentration of 3.3 • 10 -2 g/liter and at a gelatin concentration of 3.2 • 10-2 g/liter.

Articles you may be interested inEffect of V 2 O 5 concentration on structural and optical properties of WO 3 thin films prepared by RF magnetron sputtering AIP Conf.Ta-Al20 a cermet thin films were produced by diode sputtering. Cathodes were fabricated by powder techniques plasma spraying and as mechanical composites. Film compositions of 1-20 wt% Al203 produced resistivitie~ of 250 to 25 000 ~n·cm and TCR's of +100 to -450 ppm;oC, respectively. The films showed good thermal stability and could be anodized. Electron microscopy and x-ray analyses suggest a film structure consisting of long columnar grains of bcc Ta, approximately 100 A in diameter, surrounded by Al20 a . A quantitative analysis is made of tunneling currents in an idealized film. Resistivity-composition and resistivity-temperature data are explained in terms of this analysis. The height of the Ah03 barrier between grains is estimated to be 0.23 eV for an effective electron mass of 1/9. Barrier thicknesses are estimated at 15-30 A.

Aus den Grenzströmen für die Abscheidung von Cu auf einer rotierenden Pt‐ Scheibenelektrode werden die Diffusionskoeffizienten von Cu(II)‐Ionen in hochreinen wäßrigen Sulfat‐ und Fluoroborat‐Elektrolyten ermittelt.

Sn(II)‐haltige Oberflächenschichten werden auf Substraten ( ;z.B. Quarz) durch Eintauchen in salzsaure SnClz‐Lösungen erhalten.