An embodiment concerns selective etching of a structure (e.g., a fin) to form a void with the shape of the original structure. This void then functions as a mold. Flowable dielectric material fills the void to form the same shape as the original structure/mold. Post-processing then occurs (e.g., oxidation build up and annealing) to harden the dielectric in the void. The resulting product is a molded dielectric nanostructure that has the same shape as the original structure but consists of a different material (e.g., dielectric instead of silicon). Other embodiments are described herein.