Selective silicon nanoparticle growth on high-density arrays of silicon nitride

Selective silicon nanoparticle deposition from disilane on ∼17 nm diameter Si₃N₄ features defined through a 15-nm-thick SiO₂ masking layer was studied using hot wire chemical vapor deposition between 900 and 1025 K, and chemical vapor deposition between 900 and 975 K. Thin film poly(styrene-b-methyl methacrylate) diblock copolymer was used to generate cylinders with a density of 6×10¹⁰ cm^-2 that served as the patterning template. Silicon adatom etching of SiO₂ and diffusion of adatoms to the Si₃N₄ regions prevented the accumulation of adatoms necessary for nanoparticle nucleation and growth on the SiO₂ surfaces. Nanoparticles form selectively on Si₃N₄, because adsorbed Si does not etch this surface. Incident flux, total exposure, and substrate temperature were adjusted to explore nanoparticle deposition trends relating relative adatom concentration with nanoparticle density and size distributions.