Cubic-Structured HfO2 With Optimized Doping of Lanthanum for Higher Dielectric Constant

Silicon Nano Device Lab., Nat. Univ. of Singapore, Singapore
IEEE Electron Device Letters (Impact Factor: 2.75). 07/2009; 30(6):623 - 625. DOI: 10.1109/LED.2009.2020613
Source: IEEE Xplore


It is demonstrated that HfO2 films can have much higher dielectric-constant values than the usual reported value of 20-24 by optimized incorporation of lanthanum element and crystallization to cubic structure. When HfO2 with 8% La is crystallized into cubic structure, the film exhibits the kappa value of ~38 which is the highest among ever reported HfO2 -based high-kappa dielectrics. The increased kappa value of HfO2 with 8% La enables the leakage current to be reduced more than one order of magnitude lower, compared to amorphous-phase HfO2 under the same electric field. The dependence of film thickness and annealing temperature on the cubic crystallization is also reported.

6 Reads
  • Source
    • "(b) Benchmarked data on leakage current densities (at +3V) versus EOT. to form the bottom-gate electrode. A 20-nm-thick HfLaO with 8% La concentration was then deposited by an atomic layer deposition process [13]. The chamber pressure and temperature for HfLaO deposition were 0.2 torr and 300 • C, respectively. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Low-voltage and high-performance pentacene thin-film transistors with a hybrid gate dielectric consisting of ultrathin PVP (8 nm) and a high-κ HfLaO (20 nm) have been demonstrated. The hybrid gate dielectric exploits the advantages of both dielectrics, i.e., a good interface between the organic dielectric and channel material as well as the insulating properties of the inorganic metal-oxide, resulting in very low leakage current, hysteresis-free behavior, superior drain-current drivability, and successful operation at -2 V. The superior device performance is attributed to good intermolecular ordering and the large grain size of the pentacene channel layer formed on the hybrid dielectric.
    IEEE Electron Device Letters 12/2010; 31(11-31):1308 - 1310. DOI:10.1109/LED.2010.2066542 · 2.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Band alignments of La2Hf2O7 (LHO) films grown on fully depleted SiGe on insulator (FD SGOI) substrates have been investigated by x-ray photoelectron technique. The valence and conduction band offsets for LHO/FD SGOI systems are determined to be 3.25 and 1.49 eV, respectively. Such asymmetric band alignment can be modulated to be quite symmetric by the Surface nitridation of FD SGOI using NH3 treatment. The impact of NH3-treatment temperature on band offsets is also investigated. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3204459]
    Journal of Applied Physics 08/2009; 106(4). DOI:10.1063/1.3204459 · 2.18 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The control of high-symmetry phases of HfO2 can be achieved by cationic substitution for Hf. The electrical properties of HfO2 cubic phase stabilized by addition of yttrium or magnesium are investigated. The introduction of moderate Y or Mg doping content (similar to 10-15 at.%) in HfO2 results in an enhancement of the dielectric constant. No degradation of the interface state density and leakage current is noticed. The flat-band voltage is shifted to positive voltages, similarly as it was observed for monoclinic and cubic pure HfO2 thin films. This result confirms that the contribution of the SiO2/high-kappa interface to the flat-band voltage depends on the structural high-kappa properties.
    ECS Transactions; 01/2010
Show more

Similar Publications