Characteristics of ZrO2 films deposited by using the atomic layer deposition method

The physical and the electrical properties of ZrO2 dielectric film were investigated to determine if this film could be applied as a potential replacement for the SiO2 gate dielectric. ZrO2 films were successfully deposited on p-type Si substrates by using the atomic layer deposition (ALD) technique with ZrCl4 and H2O. The ZrO2 films exhibited a very low chlorine content below the detection limit of the Auger electron spectrometer and showed the stoichiometric characteristics of ZrO2. The interfacial layer formed between the ZrO2 film and the Si substrate was observed and analyzed by using X-ray photoelectron spectroscopy and was found to be Zr-silicate and/or a SiOx layer with an amorphous phase. This interfacial layer became thicker as the annealing temperature was increased. Cross-sectional transmission electron microscopy images of the ZrO2 films showed a randomly oriented polycrystalline structure. The flat-band voltage and the calculated dielectric constant of the ZrO2 film were 0.7 V and 13.7, respectively. The leakage current of the ZrO2 films was 7.5 x 10(-5) A/cm(2) at a gate bias voltage of \V-G-V-FB\ 2 Volts with an equivalent oxide thickness value of 1.9 nm.