Browsing by Author "Chang, K. P."

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Ablation of Copper by a Single Ultrashort Laser Pulse
(2014-06-01)
Wang, S. Y.
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Ren, Y. P.
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Chang, K. P.
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Cheng, C. W.
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Chen, J. K.
Thermal ablation of copper films by a single Ti:Sapphire femtosecond laser pulse of wavelength 800 nm and duration 100 fs was investigated experimentally and theoretically. The laser experiments were performed; the ablation depth and crater profiles were measured for laser fluences up to 1037 J/cm(2). A comprehensive axisymmetric model, including a two-temperature model, phase change models for rapid melting and evaporation, and a phase explosion model for ejecting metastable liquid and vapor, was developed to simulate the laser material ablation process. The simulated ablation depths and crater profiles agree well with the experimental measurements.
Effects of width scaling and layout variation on dual damascene copper interconnect electromigration
(2007-12-01)
Lin, M. H.
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Chang, K. P.
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Su, K. C.
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Wang, Tahui
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電子工程學系及電子研究所
Electromigration versus line width in the 0.12-10 mu m range and the configuration of the via/line contact in dual damascene Cu has been investigated. There are two scenarios for width scaling impact on electromigration. One is the width < 1 mu m region, in which the MTF shows a weak width dependence, except for the via-limited condition. The other is the width > 1 mu m region, in which the MTF shows a strong width dependence. A theory was proposed to explain the observed behavior. For polycrystalline lines (width > 1 mu m), the dominant diffusion paths are a mixture of grain boundary and surface diffusion. The activation energy for the dominant grain boundary transport (width > 1 mu m) is approximately 0.2 eV higher than that of the dominant surface transport (width similar to 1 mu m). The derived activation energies for grain-boundary and surface diffusion are obtained from Cu drift velocity under electromigration stressing. The mechanisms governing the electromigration lifetime of interconnects leads to via interconnect design rules for maximizing lifetime being identified. (C) 2006 Elsevier Ltd. All rights reserved.
Effects of width scaling, length scaling, and layout variation on electromigrationin in dual damascene copper interconnects
(2006)
Lin, M. H.
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Chang, K. P.
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Su, K. C.
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Wang, Tahui
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電子工程學系及電子研究所
Femtosecond laser ablation of copper at high laser fluence: Modeling and experimental comparison
(2016-01-15)
Cheng, C. W.
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Wang, S. Y.
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Chang, K. P.
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Chen, J. K.
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機械工程學系
Thermal ablation of a copper foil surface by a single femtosecond laser pulse of duration 120 fs and wavelength 800 nm was investigated herein both theoretically and experimentally. A 1D two-temperature model with temperature-dependent material properties was considered, including the extended Drude model for dynamic optical properties. The rapid phase change and phase explosion models were incorporated to simulate the material ablation process. The simulated ablation depths agree well with the experimental measurements for the high laser fluence regime ranging from 6.1 to 63.4 j/cm(2). (C) 2015 Elsevier B.V. All rights reserved.
MULTI-LEVEL OPERATION OF FULLY CMOS COMPATIBLE WOX RESISTIVE RANDOM ACCESS MEMORY (RRAM)
(2009)
Chien, W. C.
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Chen, Y. C.
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Chang, K. P.
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Lai, E. K.
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Yao, Y. D.
The multi-level operation of WOX based RRAM has been investigated. Improvement of our WOX process has produced an extended linear R-V region for our devices. By adding an electrical forming process and a program-verify algorithm we have demonstrated stable 2-bit/cell operation, with potential for 3-bit/cell. The reliability of the MLC operation has been examined and very stable high temperature retention, robust read disturb immunity and initial cycling endurance of >1,000 times have been demonstrated.
Photonic band gap of two-dimensional triangular photonic crystals with broken structural and rotational symmetries
(2006-10-01)
Chang, K. P.
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Yang, S. L.
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電子物理學系
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Department of Electrophysics
Three deformed and two rotational structures are constructed to study the effect of structural and rotational symmetries on the gap widths of E- and H-polarization bands in photonic crystals. The band structures and field patterns of a triangular lattice of hollow tellurium (Te) rods are calculated using the plane-wave method. The H-polarization band gaps are strongly affected by the interaction between the fields of the rods as the rods are deformed and affected by the reduction in the rotational symmetry as whole rods are rotated. Only the shapes of the rods affect the E-polarization band gaps as the rods are either deformed or rotated. Moreover, H-polarization modes determine the absolute photonic band gap (PBG) width as the rods are rotated, whereas E-polarization modes determine the absolute PBG width as the rods are deformed. (c) 2006 American Institute of Physics.
Photonic band gaps of polygonal and circular dielectric rods in square lattices
(2008-12-01)
Chang, K. P.
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Yang, S. L.
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Shen, L. F.
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Yang, T. J.
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電子物理學系
The plane-wave method is employed to determine the band structures and the field patterns of the photonic crystals with polygonal and circular rods in square lattices. Isotropic and anisotropic N-fold polygonal rods are used to assess the effects of the shapes and symmetries of polygonal rods on E-and H-polarization modes. The photonic band structures of the polygonal rods approach those of the circular rods as N increases above a value that is determined by the optical properties of the photonic crystal. Moreover, for comparable geometric structures, anisotropic polygonal-rod photonic crystals can provide larger absolute photonic band gaps than isotropic photonic crystals. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3039213]