Ultrathin TiO_2 Gate Dielectric Formation by Annealing of Sputtered Ti on Nitrogen Passivated Si Substrates in Nitric Oxide Ambient

摘要

We have fabricated very thin TiO_2 film (T~(eq)approx20A) by RTP oxidation of sputtered Ti in NO ambient on nitrogen passivated Si substrates. The leakage current is about two orders of magnitude lower than SiO_2 of identical T_(eq). Results show that NO passivation layer prior to Ti sputterins is critical in reducing the leakage current. XPS results show that the temperature of RTP NO oxidation of sputtered Ti is very important for achieving high quality TiO_2 films. At high oxidation temperature an SiO_2 layer is formed at the interface between TiO_2 and Si and the leakage current is approaching to that of SiO_2.