Position-Specified Formation of Epitaxial Si Grains on Thermally Oxidized Si(001) Surfaces via Isolated Nanodots

We report position-specified fabrication of epitaxial Si grains on an amorphous thermal oxide layer on Si(001) substrates. This process takes advantage of unique features of surface-sensitive deposition chemistry and nanoscale oxidation phenomena. To make the grown grains epitaxial with respect to the Si substrate, growth was initiated from Si nanodots that had been isolated from the substrate by the oxidation of mushroom-shaped overgrown structures. The position of each grain is controlled by the use of a lithographically patterned mask layer. Mechanisms of the oxidation-induced nanodot isolation, which is a key step in this fabrication process, are discussed. The present technique is applicable to the integration of various single-crystal materials onto Si substrates.