Browsing by Author "Hsu, Shih-Hsin"

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An Automatic Synthesis Tool for Nanometer Low Dropout Regulator Using Simulation Based Model and Geometric Programming
(2014-01-01)
Hsu, Shih-Hsin
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Chen, Wei-Zen
;
Zheng, Jui-Pin
;
Liu, Sean S. -Y.
;
Pan, Po-Cheng
This paper presents an efficient synthesis framework for Low Dropout Regulator (LDOs) automatic design to facilitate varieties of power management ICs applications. A four-stage synthesizer is proposed to deal with topology selection, transistor sizing, and layout generation automatically. The proposed approach correctly describes device behaviors in moderate and strong inversion regions for current optimization. Without trivial trial and error procedure, the "SPICE accuracy" device size mapping is provided, and the resulting layout is compact and regular while meeting analog design constraints. Using the proposed synthesis tool for LDO automatic design, a prototype chip has been successfully fabricated in 65nm CMOS process. The experimental results validate our methodology in industrial cases with high performance and meet all the target specifications.
Antiresonant reflecting optical waveguides polarization beam splitters
(2006-09-01)
Huang, Yang-Tung
;
Jang, Chiou-Hung
;
Hsu, Shih-Hsin
;
Deng, Jau-Jan
;
電子工程學系及電子研究所
Three different configurations of polarization beam splitters based on antiresonant reflecting optical waveguide (ARROW) structures are proposed. The polarization splittings are attained by utilizing various characteristics of basic ARROW and/or ARROW-B. In comparison with conventional waveguides, ARROW structures utilizing antiresonant reflection as the guiding mechanism can have large core sizes compatible with single-mode fibers and, thus, provide better coupling. Design principles and characteristics of these ARROW polarization beam splitters are discussed in detail, and the simulation results show that all these devices have good polarization discrimination with crosstalk < -20 dB.
Arrow based coherently coupled bending waveguides
(2005)
Tsai, Ming-Jung
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Hsu, Shih-Hsin
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Huang, Yang-Tung
;
Kwei, Cheng-May
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電子工程學系及電子研究所
Coherently coupled bending waveguides based on antiresonant reflecting optical waveguide (ARROW) structures are investigated. The ARROW structure can provide low-loss single-mode propagation with a relatively large core size for efficient connection to single-mode fibers. The flexible structural parameters of rib ARROW waveguides offer the possibility of optimization for various design considerations. For the total bending angles of 27.2 degrees and 91.2 degrees, the simulated system transmission efficiencies are -0.82 and -2.15 dB respectively. The corresponding device sizes are less than 10 mm(2).
Aspect-ratio-dependent ultra-low reflection and luminescence of dry-etched Si nanopillars on Si substrate
(2009-01-01)
Pai, Yi-Hao
;
Meng, Fan-Shuen
;
Lin, Chun-Jung
;
Kuo, Hao-Chung
;
Hsu, Shih-Hsin
The Si nanopillars with high aspect ratio were fabricated by dry-etching the thin SiO(2)-covered Si substrate with a rapidly self-assembled Ni nanodot patterned mask. Aspect-ratio-dependent ultra-low reflection and anomalous luminescence of Si nanopillars are analyzed for applications in all-Si based lighting and energy transferring systems. The Si nanopillars induce an ultra-low reflectance and refractive index of 0.88% and 1.12, respectively, at 435 nm due to the air/Si mixed structure and highly roughened surface. The reflectance can be < 10% with a corresponding refractive index of < 1.80 between 190 and 670 nm. Lengthening the Si nanopillars from 150 +/- 15 to 230 +/- 20 nm further results in a decreasing reflectance, corresponding to a reduction in refractive index by Delta n/n = 18% in the visible and near-infrared wavelength region. After dry-etching an Si wafer into Si nanopillars, the weak blue-green luminescence with double consecutive peaks at 418-451 nm is attributed to the oxygen defect (O(2-))-induced radiation, which reveals less relevance with the ultra-low-reflective Si nanopillar surface.
Characterization of Si nanorods by spectroscopic ellipsometry with efficient theoretical modeling
(2008-04-01)
Hsu, Shih-Hsin
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Liu, En-Shao
;
Chang, Yia-Chung
;
Hilfiker, James N.
;
Kim, Young Dong
Spectroscopic ellipsometry (SE) is applied to characterize Si columnar nanostructures. By employing effective medium approximation (EMA) theory, Si nanorods are treated as a graded layer with each sub-layer modeled as a mixture of Si and voids with varying porosity fraction. In addition, the rigorous coupled-wave analysis and finite-element Green's function method were used in modeling Si nanorods as a stack of disks with varying diameters and thicknesses, and the calculations are in satisfactory agreement with the measurement results. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Combined micro- and nano-scale surface textures for enhanced near-infrared light harvesting in silicon photovoltaics
(2011-03-04)
Chang, Chia-Hua
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Yu, Peichen
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Hsu, Min-Hsiang
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Tseng, Ping-Cheng
;
Chang, Wei-Lun
As silicon photovoltaics evolve towards thin-wafer technologies, efficient optical absorption for the near-infrared wavelengths has become particularly challenging. In this work, we present a solution that employs combined micro- and nano-scale surface textures to increase light harvesting in the near-infrared for crystalline silicon photovoltaics, and discuss the associated antireflection and scattering mechanisms. The surface textures are achieved by uniformly depositing a layer of indium-tin-oxide nanowhiskers on micro-grooved silicon substrates using electron-beam evaporation. The nanowhiskers facilitate optical transmission in the near-infrared by functioning as impedance matching layers with effective refractive indices gradually varying from 1 to 1.3. Materials with such unique refractive index characteristics are not readily available in nature. As a result, the solar cell with combined textures achieves over 90% external quantum efficiencies for a broad wavelength range of 460-980 nm, which is crucial to the development of advanced thin-substrate silicon solar cells.
Efficiency Enhancement of GaAs Photovoltaics Employing Antireflective Indium Tin Oxide Nanocolumns
(2009-04-27)
Yu, Peichen
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Chang, Chia-Hua
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Chiu, Ching-Hua
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Yang, Chin-Sheng
;
Yu, Jue-Chin
Highly-oriented indium tin oxide nano-columns are prepared by glancing-angle deposition with nitrogen. The tapered column profiles, which function as a graded-refiractive-index layer, offer superior antireflective characteristics. The nano-structured material serves as the conductive antireflective layer for GaAs solar cells, demonstrating a viable efficiency-boosting strategy for next-generation photovoltaics.
Photonic Crystal Slab Waveguides Based on Antiresonant Reflecting Optical Waveguide Structures
(2009-07-15)
Yang, Yu-Lin
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Hsu, Shih-Hsin
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Lu, Ming-Feng
;
Huang, Yang-Tung
;
生物科技學系
A novel two-dimensional photonic crystal slab waveguide based on an antiresonant reflecting optical waveguide (ARROW) structure is proposed and designed. Lightwaves propagating in this waveguide are confined by antiresonance reflection vertically and the photonic band gap laterally. In order to obtain the characteristics of the ARROW-based photonic crystal waveguides, the three-dimensional finite-difference time-domain simulations are performed. With a lateral adiabatic taper, a coupling efficiency of 80.3% from a single-mode fiber to the ARROW-based photonic crystal waveguide of a single-line defect is obtained. In addition, propagation losses less than 10 dB/mm and bend losses of 0.23 and 0.39 dB/bend for the designed 60 degrees and 120 degrees bends are achieved at an operating wavelength of 1.55 mu m.
Real-time Detection of alpha-Thrombin Binding to Single-Strand DNA Aptamers by a Highly Sensitive Si-Based Waveguide SPR Biosensor
(2012)
Huang, Chi-Chieh
;
Hsu, Hsin-Feng
;
Chen, Sz-Hau
;
Tsai, Kun-Yu
;
Huang, Yang-Tung
In this paper, real-time characterization of alpha-thrombin binding to single-strand DNA (ssDNA) aptamers by novel Si-based waveguide SPR biosensors has been investigated. The gold nanoparticles (AuNPs) modified with anti-thrombin antibodies were employed to bind with alpha-thrombin via strong antibody/antigen affinity for SPR signal amplification. The detection limit of 1 pM for alpha-thrombin detection was achieved.
Temperature-insensitive arrayed-waveguide gratings based on arrow structures
(2005)
Lin, Kun-Zong
;
Hsu, Shih-Hsin
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Huang, Yang-Tung
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The influence of temperature variation on the performance of arrayed-waveguide gratings (AWG) based on antiresonant reflecting optical waveguide (ARROW) structures is discussed. The ARROW structure can provide low-loss single-mode propagation with a relatively large core size for efficient connection to single-mode fibers. By introducing an overlay with an opposite temperature coefficient to the original waveguide structure, the temperature dependence on AWG performance can be reduced. Design of temperature-insensitive ARROW-based AWG devices is analyzed, and the channel passband shift of the proposed structure can be lowered to 0.002 nm/K.