SELECTIVE METALLIZATION OF SILICON SURFACES - THE ADSORPTION OF STERICALLY STABILIZED PALLADIUM PARTICLES ON H-TERMINATED SI(100), SI3N4, AND SIO2

The adsorption of nanometer-sized, palladium-phosphorus particles (Pd0.86P0.14) onto Si3N4, SiO2, and H-terminated Si(100) surfaces is described. These colloidal particles were prepared in aqueous solution by the reduction of Pd2+ with hypophosphite in the presence of polyvinylpyrrolidone (PVP). The sterically stabilized particles catalyze Ni deposition from an electroless solution. High resolution electron microscopy shows that the particle size decreases with increasing PVP concentration in the sol. Several monocrystalline domains were observed in all particle samples. The surface affinity of Pd particles, covered with PVP, and of ''free'' PVP molecules (i.e., not associated with Pd particles) depends strongly on the type of surface. The large differences in Pd coverage between different types of surface (e.g., Si3N4 and SiO2) offer interesting possibilities for novel pattern-wise electroless metallization procedures.