Wirelike growth of self-assembled hafnium silicides:oxide mediated epitaxy

Applied Surface Science 239(3-4) 268-272

https://doi.org/10.1016/j.apsusc.2004.06.013

Jung-Ho Lee

Abstract

A wirelike shape of Hf silicides, which is not observed in silicides directly grown on Si (001), has been obtained by oxide mediated epitaxy (OME). Hafnium deposition (∼0.4 and ∼0.2ML) onto ultrathin (∼1nm) SiO2 and annealing at 900°C resulted in the formation of self-assembled wirelike silicides via a silicate phase (Hf–O–Si bonding units) in the 600–800°C temperature range. Silicide nanowires were found to be encapsulated in the bundle aggregates. The number density of OME-grown silicides apparently decreased as a form of nanowire bundles along with an increasing aspect ratio compared with the directly grown disilicides on Si (001). This finding has an implication for the use of an ultrathin SiO2 layer in controlling the tradeoff between the number density and the aspect ratio of self-assembled silicides.