Evidence of interface conversion and electrical characteristics improvement of ultra-thin HfTiO films upon rapid thermal annealing

Ultra-thin HfTiO films were grown on Si substrate and subjected to rapid thermal annealing at 400 °C, 500 °C, 600 °C, and 700 °C in nitrogen ambient. The interface of the as deposited film is formed by SiOx and silicate, but after annealing at 600 °C, interfacial SiOx completely converted into silicate. The film annealed at 600 °C has the highest k value of 45.9, the smallest equivalent oxide thickness of 0.8 nm with the physical thickness of 9.4 nm, the lowest leakage current density of 3.1 × 10−6 A/cm−2 at bias voltage of −1 V, which shows excellent electrical properties.