Improvement in the interfacial properties and electrical characteristics of ultrathin SiO<inf>2</inf> by selective AC anodisation

In this paper we have studied the effect of selective anodisation under ac bias on ultrathin (2–2.75 nm) silicon dioxide grown at 800°C. It is shown that ac anodisation is more effective in improving the electrical properties of the ultrathin oxide compared to selective anodisation carried out under dc condition. Unlike dc anodisation, which only repairs the pinholes but does not improve the interfacial properties, ac anodisation is found to reduce the density of interface states. The efficacy of ac anodisation is found to depend on the ac signal frequency and best results have been obtained at a frequency of 5 kHz. © 2006 Taylor & Francis Group, LLC.