Structure and electrical properties of HfO2 high- k films prepared by pulsed laser deposition on Si (100)

Applied Physics A (Impact Factor: 1.69). 10/2008; 93(3):681-684. DOI: 10.1007/s00339-008-4695-8

ABSTRACT High-k gate dielectric hafnium dioxide films were grown on Si (100) substrate by pulsed laser deposition at room temperature. The
as-deposited films were amorphous and that were monoclinic and orthorhombic after annealed at 500°C in air and N2 atmosphere, respectively. After annealed, the accumulation capacitance values increase rapidly and the flat-band voltage
shifts from −1.34V to 0.449V due to the generation of negative charges via post-annealing. The dielectric constant is in
the range of 8–40 depending on the microstructure. The I–V curve indicates that the films possess of a promising low leakage
current density of 4.2×10−8A/cm2 at the applied voltage of −1.5V.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Polycrystalline p-type CuxO films were deposited after the growth of HfO2 dielectric on Si substrate by pulsed laser deposition, and CuxO metal-oxide-semiconductor (MOS) capacitors with HfO2/SiO2 stack gate dielectric were primarily fabricated and investigated. X-ray diffraction and X-ray photoelectron spectroscopy were applied to analyze crystalline structure and Cu+/Cu2+ ratios of CuxO films respectively. SiO2 interlayer formed between the high-κ dielectric and substrate was estimated by the transmission electron microscope. Results of electrical characteristic measurement indicate that the permittivity of HfO2 is about 22, and the gate leakage current density of MOS capacitor with 11.3 nm HfO2/SiO2 stack dielectrics is ∼ 10−4 A/cm2. Results also show that the annealing in N2 can improve the quality of CuxO/HfO2 interface and thus reduce the gate leakage density.
    Thin Solid Films 05/2010; 518(15):4446–4449. · 1.87 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nitrogen is incorporated into thin HfO2 films by pulsed laser deposition using in situ ionized nitrogen. The improved thermal stability and interfacial microstructure are further confirmed by high-resolution transmission electron microscopy. The composition of the thin film is investigated by x-ray photoelectron spectroscopy and electron energy-loss spectroscopy. Electrical studies show a property permittivity of 27.7 and low leakage current density were achieved by incorporation of a small amount (about 1 at. %) of nitrogen. The dominant conduction mechanisms of the Pt/HfO2/p-Si structure are trap-assisted tunneling and Schottky emission at low electric field for the gate and substrate injection, respectively.
    Applied Physics Letters 07/2009; 95(3). · 3.52 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hafnium oxynitride films are deposited from a Hf target employing direct current magnetron sputtering in an Ar-O2-N2 atmosphere. It is shown that the presence of N2 allows for the stabilization of the transition zone between the metallic and the compound sputtering mode enabling deposition of films at well defined conditions of target coverage by varying the O2 partial pressure. Plasma analysis reveals that this experimental strategy facilitates control over the flux of the O- ions which are generated on the oxidized target surface and accelerated by the negative target potential toward the growing film. An arrangement that enables film growth without O- ion bombardment is also implemented. Moreover, stabilization of the transition sputtering zone and control of the O- ion flux without N2 addition is achieved employing high power pulsed magnetron sputtering. Structural characterization of the deposited films unambiguously proves that the phase formation of hafnium oxide and hafnium oxynitride films with the crystal structure of HfO2 is independent from the O- bombardment conditions. Experimental and theoretical data indicate that the presence of vacancies and/or the substitution of O by N atoms in the nonmetal sublattice favor the formation of the cubic and/or the tetragonal HfO2 crystal structure at the expense of the monoclinic HfO2 one.
    Journal of Applied Physics 01/2010; 108(1):4904-014904. · 2.19 Impact Factor