THE MORPHOLOGY OF ELECTROLESS NI DEPOSITION ON A COLLOIDAL PD(II) CATALYST

The surface morphology of a surface-bound colloidal Pd(II) catalyst and its effect on the particle size of an electroless Ni deposit is examined. The deposited catalyst is found to have a broad distribution of particle sizes with the largest particles reaching approximately 50 nm in diameter. Catalyst surface coverages as low as 20% are found to be sufficient to initiate complete and homogenous metallization. The distribution of particle sizes for the electroless metal deposit, found to be a function of plating time, is broad with the maximum Ni particle size exceeding 120 nm. Results indicate controlling the size of the bound catalyst is the principal determining factor in controlling the particle size of the electroless deposit. Modification of the surface by depleting the concentration of surface functional groups capable of binding catalyst is used to shift the size distribution of bound catalyst to smaller values. A resulting three- to fourfold reduction in the particle size of the electroless deposit is demonstrated.