Ultrathin TiO2 gate dielectric formation by annealing of sputtered Ti on nitrogen passivated Si substrates in nitric oxide ambient

We have fabricated very thin TiO2 film (T(eq)similar to 20 Angstrom) 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 SiO2 of identical T-eq. Results show that NO passivation layer prior to Ti sputtering 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 TiO2 films. At high oxidation temperature an SiO2 layer is formed at the interface between TiO2 and Si and the leakage current is approaching to that of SiO2.