Evidence of Co/SiO2 reaction during rapid thermal annealing

Abstract

Cobalt (Co)/silicon dioxide (SiO2) reactions during rapid thermal annealing (RTA) in an N2 ambient have been investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that islands consisting of Co and the cobalt oxide phase, Co3O4, form during high-temperature anneals (30 s−10 min at 800 °C). After a selective wet etch to remove the islands, groove-like features are produced in the SiO2 layer. The morphologies of the islands and grooves are strikingly similar, which strongly suggest that Co and the underlying SiO2 layer have reacted, most likely to form Co3O4. We propose that small concentrations of O2 are necessary to promote Co/SiO2 interactions.