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Abstract: Hafnium dioxide (HfO2) thin films were deposited on a quartz substrate by RF reactive magnetron sputtering. The influence of O2/Ar flow ratio on the deposition rate, structure and optical properties of HfO2 thin films were systematically studied using X-ray diffraction (XRD), scan electron microscopy (SEM) and UV–visible spectroscopy. The results show that the deposition rate decreases obviously when the O2/Ar flow ratio increases from 0 to 0.25 and then, decreases little as the O2/Ar flow ratio further increases to 0.50. The HfO2 thin films prepared are all polycrystalline with a monoclinic phase. The thin film deposited with pure argon shows a preferential growth and has considerably improved crystallinity and much larger crystallite size. Meanwhile, after oxygen is introduced into the deposition, the thin films prepared have random orientation, weakened crystallinity and smaller crystallite size. The refractive index is higher for the thin film deposited without oxygen and increases as the O2/Ar flow ratio increases from 0.25 to 0.50. The band gap energy of the thin film increases with an increasing O2/Ar flow ratio. [ABSTRACT FROM AUTHOR]

Abstract: Hafnium dioxide (HfO2) thin films were prepared by radio frequency (RF) magnetron sputtering at various RF powers. The influence of RF power on the structure and optical properties of the HfO2 thin films were studied systematically by X-ray diffraction (XRD), ultraviolet-visible transmission spectrum and Fourier transform infrared (FTIR) spectrum. The results show that the thin films are polycrystalline, the crystallization is improved and the crystallite size has its minimum value for the thin film deposited at the RF power of 110W. The refractive index and band gap energy of the thin films both increase firstly and then decrease with the increased RF power. The further study reveals that the antireflective effect in certain infrared waveband, such as 3–5μm and 8–12μm, can be achieved in the HfO2/Si/HfO2 system, indicating an excellent infrared antireflective coating of HfO2 thin film. [Copyright &y& Elsevier]

Abstract: HfO2 thin films have been deposited on Si substrate by radio frequency reactive magnetron sputtering. The optical and structural properties of HfO2 thin films in relation to rapid thermal annealing (RTA) temperatures are investigated by spectroscopic ellipsometry (SE), X-ray diffraction (XRD) and UV Raman spectrum. XRD and Raman measurements show that the as-deposited films are mainly amorphous and a transition to a crystalline phase occurs after RTA. Based on a parameterized Tauc–Lorentz dispersion model, the optical constants of the as-deposited and annealed films are systematically extracted. With increased annealing temperature, the refractive index n and the extinction coefficient k are observed to increase. The changes of the complex dielectric functions with annealing temperature are also discussed. [Copyright &y& Elsevier]

Abstract: The chemical structure and electrical properties of HfO2 thin film grown by rf reactive magnetron sputtering after rapid thermal annealing (RTA) were investigated. The chemical composition of HfO2 films and interfacial chemical structure of HfO2/Si in relation to the RTA process were examined by X-ray photoelectron spectroscopy. Hf 4f and O 1s core level spectra suggest that the as-deposited HfO2 film is nonstoichiometric and the peaks shift towards lower binding energy after RTA. The Hf–Si bonds at the HfO2/Si interface can be broken after RTA to form Hf–Si–O bonds. The electrical characteristics of HfO2 films were determined by capacitance–voltage (C–V) and current density–voltage (J–V) measurements. The results showed that the density of fixed charge and leakage current density of HfO2 film were decreased after the RTA process in N2 atmosphere. [Copyright &y& Elsevier]

Abstract: The conduction mechanism and the behavior of stress-induced leakage current (SILC) through the HfO2 high-k layers in metal-oxide-semiconductor (MOS) structures have been investigated. Assisted tunneling of electrons via stress-induced interface traps and bulk oxide traps are responsible for the SILC generation in HfO2 dielectric. This trapping process depends on the polarity of the applied gate voltage and oxide thickness. The current conduction mechanism of the HfO2 films is dominated by Poole–Frenkel emission under substrate injection in the region from 1.5MV/cm to 2.6MV/cm, confirming that the SILC mechanism is related to the trapping process. [Copyright &y& Elsevier]