Electrical properties of dielectric and ferroelectric films prepared by plasma enhanced atomic layer deposition

High dielectric SrTa2O6 films and ferroelectric SBT films were prepared by alternating supply of sources and O-2 plasma for PEALD process. It was observed that the uniform and conformal thin films were successfully deposited using PEALD. The dielectric constants and the dissipation factors of Pt/STO/Pt structures showed slight increase up to 700degreesC and a considerable increase in STO annealed at 800degreesC. The leakage current density of a 40nm-STO film was about 5x10(-8) A/cm(2) at 3V. The STO MOS capacitors shows a good interface states with efficiently low fixed charge and interface trapped charge. These electrical properties support the possibility of STO oxide application to a new high-k gate dielectric. PEALD-SBT films annealed at 750degreesC in O-2 showed typical ferroelectric property. The remanent polarization (P-r) of a 100nm-SBT film is about 4muC/cm(2) at 5V-sweep voltage and the fatigue-free property after 1x10(11) cycles was observed.