Patterning of Solid Films via Selective Atomic Layer Deposition Based on Silylation and UV/Ozonolysis

A simple methodology was successfully demonstrated for the nanoscale patterning of silicon wafers. Thin films are grown by atomic layer deposition (ALD) and patterned by using selective surface chemistry: First, all the nucleation sites on the original oxide surface are silylated in order to render them unreactive; then, a pattern is developed by selective removal of the silylation agent using a mask and a combination of ultraviolet radiation and ozonolysis. Subsequent ALD is carried out selectively on the areas where the silylation moieties have been removed. This simple procedure affords patterning of oxide surfaces with monolayer control and a lateral resolution on the order of a few tens of nanometers or better. Other selective ALD processes have shown only limited discrimination during deposition, but our method shows absolute inhibition of film growth on the silylated areas while films as thick as 10 nm are grown on the re-exposed sectors. Our example involved the deposition of hafnium oxide films on the native silicon oxide film that forms on Si(100) wafers, but we believe that the approach is general and easily extendable to other ALD processes.