3,798 research outputs found
Effect of precursors on the morphology of lithium aluminate prepared by hydrothermal treatment
No full textHydrothermal treatment method was proposed to prepare pure LiAlO2 with fibrous crystal morphology and the effect of precursors on the morphology of lithium aluminate was investigated. Lithium butoxide-aluminum butoxide system gave mostly rod-like beta-LiAlO2 crystal. As the length of alkoxy group decreases, the fraction of plate shape crystals was increased and boehmite was dominant crystal phase. Needle-shape beta-LiAlO2 was produced from lithium nitrate-aluminum butoxide-sodium hydroxide system with the mole ratio of 6 : 1 : 3, respectively. beta-LiAlO2 prepared by hydrothermal treatment was transformed to gamma-LiAlO2 at 750-850 degrees C. The specific surface area of gamma-LiAlO2 powders was above 10 m(2)/g. (C) 2000 Kluwer Academic Publishers
PEALD of a ruthenium adhesion layer for copper interconnects
No full textRuthenium thin films were produced by plasma-enhanced atomic layer deposition (PEALD) using an alternating supply of bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)(2)] and NH3 plasma at a deposition temperature of 270 degreesC. The film thickness per cycle was self-limited at 0.038 nm/cycle, which was thinner than the thickness obtained from the conventional ALD using oxygen instead of NH3 plasma. The ruthenium thin film prepared with PEALD had a preferential orientation toward (002), and it was progressively promoted with NH3 plasma power. The PEALD of ruthenium shows a merit in controlling ultrathin film thickness with less than 2 nm more precisely and more easily than the conventional ALD, due to the reduced transient period at the initial film growth stage. Also, ruthenium thin film improved the interfacial adhesion of metallorganic chemical vapor deposited copper to diffusion barrier metals by forming Cu-Ru chemical bonds at the interface without degrading the film resistivity of copper. (C) 2004 The Electrochemical Society.This work was supported by the project of National Research Laboratory (NRL).
The Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
Plasma-enhanced atomic layer deposition of ruthenium thin films
No full textPlasma-enhanced atomic layer deposition (PEALD) of ruthenium thin films was performed using an alternate supply of bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)(2)] and NH3 plasma. NH3 plasma acted as an effective reducing agent for Ru(EtCp)(2). The ruthenium film formed during one deposition cycle was saturated at 0.038 nm/cycle, and its resistivity was 12 muOmega cm. No carbon or nitrogen impurities were incorporated in the film as determined by elastic recoil detection time of flight. The film density was higher than that formed by a conventional ALD, in which oxygen was used. The root-mean-square surface roughness of a 50 nm thick PELAD ruthenium film was 0.7 nm. (C) 2004 The Electrochemical Society.This work was supported by the project of National Research Laboratory ~NRL!.
Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
Plasma-enhanced atomic layer deposition of Ru-TiN thin films for copper diffusion barrier metals
No full textRuthenium-titanium nitride (Ru-TiN) thin films were grown by plasma-enhanced atomic layer deposition (PEALD) at a growth temperature of 200 degrees C. For the Ru - TiN PEALD, Ru and TiN were sequentially deposited to intermix TiN with Ru. The composition of Ru - TiN films was controlled by changing the number of deposition cycles allocated to Ru, while the number of deposition cycles for TiN was fixed to one cycle. The microstructures of Ru - TiN films changed from polycrystalline to amorphous, as the intermixing ratio of Ru increased in the deposited Ru - TiN films. The resistivity of the Ru - TiN film was abruptly increased by adding Ru at the first stage, but after showing a peak resistivity, it decreased with the intermixing ratio of Ru in the films. Especially, the film of Ru-0.67 -(TiN)(0.33) showed an electrical resistivity of 190 mu Omega cm. As a Cu diffusion barrier layer, amorphous Ru - TiN films showed a superior copper diffusion barrier property to TiN or Ru itself, which had a polycrystalline structure. Moreover, Ru - TiN films showed a good adhesion to both chemical vapor deposition copper and an underlayer of SiO2. (C) 2006 The Electrochemical Society.This work was supported by the project of System IC 2010.
Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
The formation of phase pure lithium aluminate from the bulky lithium and aluminum alkoxides
No full textLow degradation and high annealing effects of amorphous silicon multilayer processed through alternate hydrogen dilution
No full textRelativistic cyclotron motion in a polarized electric field
No full textThe relativistic cyclotron motion in a uniform magnetic field and in a transverse time-periodic electric field is studied, with particular attention to qualitative differences in the nature of the motion under linearly and circularly polarized electric fields. Theoretical analysis based on the Lagrangian formulation of the cyclotron motion allows a direct comparision for the two polarizations and confirms the earlier observation that the cyclotron motion is always integrable when the electric field is circularly polarized, but is not under a linearly polarized electric field
Pipelined Cartesian-to-polar coordinate conversion based on SRT division
No full textThis brief proposes a new Cartesian-to-polar coordinate conversion technique based on the radix-4 SRT division. The coarse quotient is used to derive the magnitude and the coarse phase by referring to tables, while the fine quotient is applied to linearly interpolate the fine phase to be added to the coarse phase. Compared to the CORDIC-based techniques, the proposed conversion requires less internal word-length and provides parallelism between internal stages, resulting in reduced computation latency and small chip area. A prototype chip designed using 0.25-mu m CMOS technology occupies 0.203 mm(2), and post-layout simulations show maximum frequency of 400 MHz and power consumption of 170 mW at 2.5 V.This work was
supported in part by Institute of Information Technology Assessment through
the ITRC. This brief was recommended by Associate Editor S. Tsukiyama
SLIDING MODE CONTROL OF A ZERO-CURRENT SWITCHING RESONANT CONVERTER
No full textA closed-loop output voltage control method for QSRC using a sliding mode control is presented. Because the closed-loop system can be reduced from 3rd order to 2nd order, the system design becomes very much simplified. It is shown that the dynamic ranges of the output voltage and load resistance are very large, and that the dynamic behaviour of the sliding mode control is not affected by input voltage, showing the robustness of the sliding mode control technique. These features are verified by computer simulations and experiments with good agreement
- …
