Cubic-Structured HfO2 With Optimized Doping of Lanthanum for Higher Dielectric Constant
ABSTRACT 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.
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- "(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 . The chamber pressure and temperature for HfLaO deposition were 0.2 torr and 300 • C, respectively. "
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; DOI:10.1109/LED.2010.2066542 · 3.02 Impact Factor
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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 · 2.19 Impact Factor
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ABSTRACT: Metal-insulator-metal (MIM) capacitors fabricated with (8%) La-doped HfO<sub>2</sub> single layer as well as HfLaO/ LaAlO<sub>3</sub>/HfLaO multilayer dielectric stack are demonstrated. While the La-doped HfO<sub>2</sub> single layer is crystallized at 420<sup>??</sup>C annealing, HfLaO/LaAlO<sub>3</sub>/HfLaO multilayer dielectric stack remains amorphous. A high dielectric-constant value of 38 can be obtained when 8% La-doped HfO<sub>2</sub> is crystallized into cubiclike structure. However, it is observed that the linearity of MIM capacitor is degraded upon crystallization. The multilayer film has lower average dielectric constant but shows low quadratic voltage linearity of less than 1000 ppm/V<sup>2</sup> up to a capacitance density of 9 fF/??m<sup>2</sup> . It is observed that the HfLaO single-layer MIM is suitable for the applications with requirements of high capacitance density and robust reliability, while the multilayer MIM is suitable for a precision circuit.IEEE Electron Device Letters 02/2010; 31(1-31):17 - 19. DOI:10.1109/LED.2009.2034545 · 3.02 Impact Factor