Ru nanostructure fabrication using an anodic aluminum oxide nanotemplate and highlyconformal Ru atomic layer deposition

Abstract

We fabricated metallic nanostructures directly on Si substrates through a hybrid nanoprocesscombining atomic layer deposition (ALD) and a self-assembled anodic aluminum oxide(AAO) nanotemplate. ALD Ru films with Ru(DMPD)(EtCp) as a precursor andO2 as a reactant exhibited high purity and low resistivity with negligible nucleation delay andlow roughness. These good growth characteristics resulted in the excellent conformality fornanometer-scale vias and trenches. Additionally, AAO nanotemplates were fabricated directlyon Si and Ti/Si substrates through a multiple anodization process. AAO nanotemplates withvarious hole sizes (30–100 nm) and aspect ratios (2:1–20:1) were fabricated by controllingthe anodizing process parameters. The barrier layers between AAO nanotemplatesand Si substrates were completely removed by reactive ion etching (RIE) usingBCl3 plasma. By combining the ALD Ru and the AAO nanotemplate, Ru nanostructures with controllablesizes and shapes were prepared on Si and Ti/Si substrates. The Ru nanowire array devices as aplatform for sensor devices exhibited befitting properties of good ohmic contact and highsurface/volume ratio.