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Equivalent Oxide Thickness (equivalent + oxide_thickness)
Selected AbstractsCapacitors with an Equivalent Oxide Thickness of <0.5 nm for Nanoscale Electronic Semiconductor MemoryADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Seong Keun Kim Abstract The recent progress in the metal-insulator-metal (MIM) capacitor technology is reviewed in terms of the materials and processes mostly for dynamic random access memory (DRAM) applications. As TiN/ZrO2 -Al2O3 -ZrO2/TiN (ZAZ) type DRAM capacitors approach their technical limits, there has been renewed interest in the perovskite SrTiO3, which has a dielectric constant of >100, even at a thickness ,10 nm. However, there are many technical challenges to overcome before this type of MIM capacitor can be used in mass-production compatible processes despite the large advancements in atomic layer deposition (ALD) technology over the past decade. In the mean time, rutile structure TiO2 and Al-doped TiO2 films might find space to fill the gap between ZAZ and SrTiO3 MIM capacitors due to their exceptionally high dielectric constant among binary oxides. Achieving a uniform and dense rutile structure is the key technology for the TiO2 -based dielectrics, which depends on having a dense, uniform and smooth RuO2 layer as bottom electrode. Although the Ru (and RuO2) layers grown by ALD using metal-organic precursors are promising, recent technological breakthroughs using the RuO4 precursor made a thin, uniform, and denser Ru and RuO2 layer on a TiN electrode. A minimum equivalent oxide thickness as small as 0.45 nm with a low enough leakage current was confirmed, even in laboratory scale experiments. The bulk dielectric constant of ALD SrTiO3 films, grown at 370 °C, was ,150 even with thicknesses ,15 nm. The recent development of novel group II precursors made it possible to increase the growth rate largely while leaving the electrical properties of the ALD SrTiO3 film intact. This is an important advancement toward the commercial applications of these MIM capacitors to DRAM as well as to other fields, where an extremely high capacitor density and three-dimensional structures are necessary. [source] Elasticity, electronic structure, and dielectric property of cubic SrHfO3 from first-principlesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2009Z. F. Hou Abstract Recently, SrHfO3 compound was proposed as a potential gate dielectric to fabricate metal,oxide,semiconductor field-effect transistors (MOSFET) with equivalent oxide thickness (EOT) below 1 nm. Here we report the elasticity, electronic structure, and dielectric property of cubic SrHfO3 from first-principle study based on the plane-wave pseudopotential method within the local density approximation (LDA). The independent elastic constants of cubic SrHfO3 are derived from the derivative of total energy as a function of lattice strain. The elastic modulus is predicted from Voight-Hill bounds. The Born effective charges, electronic dielectric tensors, long wavelength phonon frequencies, and LO,TO splitting of cubic SrHfO3 are computed by linear response with density functional perturbation theory (DFPT). The calculated lattice constant and bulk modulus of cubic SrHfO3 are in good agreement with the available experimental data and other theoretical results. Our results show cubic SrHfO3 is a ductile insulator with an indirect band gap of 3.74 eV (LDA value) and electric dielectric tensor of 4.43, Hf 5d states and O 2p states exhibit a strong hybridization, and cubic SrHfO3 can be mechanically stable. In addition, the phonon frequency of ,soft mode' at zone-center also agrees well with previous theoretical value. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Tunneling current in gate dielectric stack in sub-45 nanometer CMOS devicesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2009Hitender Kumar Tyagi Abstract Direct tunneling current through dual layer SiO2/high-K dielectric structures are investigated for substrate injection. Correlation of dielectric constants and band offsets with respect to silicon has been taken into consideration in order to identify possible materials to construct these devices. The direct tunneling current in oxide/high-K dielectric structures with equivalent oxide thickness (EOT) of 2.0 nm can be significantly lower than that through single layer oxides of the same thickness. Various structures and materials of high-K stacks of interest have been examined and compared to access the reduction of gate current in these structures. It is estimated that HfO2/SiO2 dual stack structure can reduce gate leakage current by four orders of magnitude as compared with pure SiO2 layer of same EOT. The importance of interfacial layer in dual stack structure is high-lighted for the reduction of gate leakage current. The present approach is capable of modeling high-K stack structures consisting of multiple layers of different dielectrics (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Atomic Layer Deposition of BaTiO3 Thin Films,Effect of Barium Hydroxide FormationCHEMICAL VAPOR DEPOSITION, Issue 5 2007M. Vehkamäki Abstract Barium titanate thin films are grown by atomic layer deposition (ALD) at 340,°C from barium cyclopentienyl and titanium methoxide precursors. H2O is used as the oxygen source. Binary reactions of Ba(tBu3C5H2)2 and H2O are first studied separately in BaO deposition and are found to result in a hydration/dehydration cycle, which is strongly influenced by the process temperature. Self-limiting growth of amorphous barium titanate films becomes possible when Ti(OMe)4 , H2O growth cycles are mixed as well as possible with Ba(tBu3C5H2)2 , H2O cycles. The as-deposited amorphous films are crystallized by post-deposition annealing at 600,°C. Permittivities of 15 and 70 are measured for as-deposited and post-deposition annealed films, respectively. A charge density of 1.9 ,C cm,2 (equivalent oxide thickness of 1.8,nm) and leakage current density ,,1,×,10,7,A,cm,2 were achieved at 1,V bias with a 32,nm thick Ba,Ti,O film in a Pt electrode stack annealed at 600,°C. [source] Thin Films of ZrO2 for High- k Applications Employing Engineered Alkoxide- and Amide-Based MOCVD Precursors,CHEMICAL VAPOR DEPOSITION, Issue 2-3 2007R. Thomas Abstract Ultrathin ZrO2 films were deposited on SiOx/Si in a multiwafer planetary metal-organic (MO)CVD reactor combined with a liquid delivery system. Two different alkoxide-based precursors, [Zr(OiPr)2(tbaoac)2] and [Zr(OtBu)2(tbaoac)2] are compared with two amide-based precursors, [Zr(NEt2)2(dbml)2] and [Zr(NEtMe)2(guanid)2]. Growth rate, surface roughness, density, and crystallization behavior are compared over a wide range of deposition temperatures (400,700,°C). In addition, the influence of the solvents, n -butylacetate, toluene, and hexane, is discussed. The best growth results in terms of low temperature deposition rate, surface roughness, film density, and carbon content were obtained for the new [Zr(NEtMe)2(guanid)2] precursor. The electrical properties were investigated with metal,insulator,semiconductor (MIS) capacitors. The relative dielectric permittivity was in the range 17,24, depending on the precursor. Compared to standard SiO2 capacitors of similar equivalent oxide thickness, low leakage currents were obtained. [source] Preparation and electrical characterization of amorphous BaO, SrO and Ba0.7Sr0.3O as high-k gate dielectricsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2010D. Müller-Sajak Abstract We report on the measurement of band offsets and electrical characterizations of amorphous BaO, SrO and Ba0.7Sr0.3O as alternative gate oxides grown on n-Si(001) at room temperature without further treatments. These materials provide relative dielectric constants close to those expected from bulk values even for ultra-thin films (equivalent oxide thicknesses below 1 nm) and posess very low rechargeable trap densities. Interface defect densities are comparable to other high-k materials for BaO and SrO films, but an order of magnitude lower for Ba0.7Sr0.3O. This demonstrates the importance of both chemical and structural interface effects (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||