Interface and electrical properties of ultra-thin HfO2 film grown by radio frequency sputtering

Interfacial composition and electrical properties of ultra-thin hafnium oxide (HfO2) films on p-type < 100 > Si substrate are reported. Hafnium oxide (HfO2) thin films are prepared using radio-frequency sputtering method and subsequently annealed at different temperature. The effect of post-deposition annealing on the interfacial and chemical state of HfO2/Si gate stack has been characterised by means of X-ray reflectivity and X-ray photoelectron spectroscopy studies. Peaks of X-ray photoelectron spectroscopy spectra at 530.50 and 532.25 eV originate from Hf-O-Si bond illustrated the creation of Hf-silicate based interfacial layer at the high-k/Si interface. X-ray reflectivity fitting result also corroborated the formation of Hf silicate interfacial layer. Capacitance-voltage measurements revealed insignificant hysteresis in case of film annealed at 600 C. Interface trap density has been extracted using Terman method and is found to be 318 x 10(-11) cm(-2) eV(-1) at 1.0 V. Minimum equivalent oxide thickness (EOT) of 1.3 nm was obtained for the film annealed at 600 degrees C. The gate leakage current density of the HfO2 film annealed at 600 degrees C is 1.5 x 10-5 A/cm(2) at a bias voltage of 2 V. (C) 2015 Elsevier B.V. All rights reserved.