Browsing by Author "Wu, C. W."

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Cell Endurance Prediction from a Large-area SONOS Capacitor
(2009)
Lee, C. H.
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Tu, W. H.
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Gu, S. H.
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Wu, C. W.
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Lin, S. W.
Endurance considerations induced by the degadation of top and bottom oxides are proposed for a SONOS memory. First, a correlation is found between the widespread C-V curves induced by interface generation and cycling numbers (cyc. #). Unlike V-FB (accumulation region), V-T (inversion region) shows a much severe shift. Inter-face state (N-it) is identified as a key factor even when a 2nm bottom oxide is used. Moreover, charge to breakdown (Q(BD)) for an ONO capacitor under positive and negative constant current stress (CCS) is investigated. Our study reveals that QBD of such stacks strongly depends on the top oxide thickness. A field enhancement induced by charges in a trapping nitride layer is the root cause. Based on Weibull statistics, the risk of dielectric breakdown for both blocking layers is then evaluated.
Design and simulation of a MEMS high G inertial impact sensor
(2008)
Wang, Y. P.
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Hsu, R. Q.
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Wu, C. W.
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機械工程學系
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Department of Mechanical Engineering
Conventional inertial impact sensors typically use mechanisms such as cantilever beams or axial springs as triggering devices. Reaction time for these conventional impact sensors are either far too slow or, in many cases, fail to function completely for high G applications. In this study, a MEMS high G inertial impact sensor with a measurement range of 8,000-21,000 G is presented. The triggering mechanism is a combination of cantilever and spring structure. The design of the mechanism underwent a series of analyses. Simulation results indicated that a MEMS high G inertial impact sensor has a faster reaction time than conventional G inertial impact sensors that use a cantilever beam or spring mechanism. Furthermore, the MEMS high G inertial impact sensor is sufficiently robust to survive the impact encountered in high G application where most conventional G inertial impact sensors fail.
Design and Test of a MEMS-Based High G Smart Sensor
(2011-04-01)
Wang, Y. P.
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Hsu, R. Q.
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Wu, C. W.
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機械工程學系
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Department of Mechanical Engineering
Most conventional G sensors use cantilever beams or axial springs as triggering devices. The reaction time of these conventional G sensors are often far too long. In many high G (> 300 G) applications, they completely fail to function. This study proposed a microelectromechanical systems-based high G smart sensor, which not only functions at a very high G impact but also identifies the material when a projectile makes an impact on a hard object. This high G smart sensor is intended for use at 3000-21 000 G. The sensor was made of silicon and the triggering mechanism involves a cantilever and a spring structure. The mechanical sensitivity of the sensors can be adjusted to preset the triggering G value. Four sensors, each designated to trigger its own G value were integrated in a unit. Experiments demonstrated that this unit can identify the characteristics of an object.
ENHANCED ANGULAR RESPONSE OF POWER CONVERSION EFFICIENCY FOR SILICON SOLAR CELLS UTILIZING A UNIFORMLY DISTRIBUTED NANO-WHISKER MEDIUM
(2010)
Chang, C. H.
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Hsu, M. H.
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Chang, W. L.
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Sun, W. C.
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Wu, C. W.
In the research of photovoltaic devices, eliminating Fresnel reflection loss is a critical issue on the way to pursue higher efficiency. To maximize the power conversion efficiency, dielectric anti reflective coating shows a cost-effective approach, but not enough to absorb broadband solar radiation effectively. Recently, the functional nanostructure shows high potential to be an omnidirectional anti reflective coating for the photovoltaic devices. Here we demonstrate Indium-Tin-Oxide (ITO) nano-whiskers, grown by the self-catalyst vapor-liquid-solid (VLS) mechanisms on the textured Si substrate. The ITO nano-whiskers can provide broadband anti-reflective properties (R < 5%) in the wavelength range of 350-1100nm. In comparison with conventional Si solar cell, the ITO nano-whiskers coating solar cell shows higher external quantum efficiency (EQE) in the range of 700-1100nm. Moreover, the ITO nano-whisker coating Si solar cell shows a high total efficiency increase of 1.1% (from 16.08% to 17.18%). The angular response of the conversion efficiency also increases from 7% at the normal incidence to more than 15% for incident angles over 70 degrees.
Finite Element Analysis of a MEMS-Based High G Inertial Shock Sensor
(2008)
Wang, Y. P.
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Hsu, R. Q.
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Wu, C. W.
;
機械工程學系
;
Department of Mechanical Engineering
Conventional mechanical inertial shock sensors typically use mechanisms such as cantilever beams or axial springs as triggering devices. Reaction time for these conventional shock sensors are either far too slow or, in many cases, fail to function completely for high G (> 300G) applications. In this study, a Micro-Electro-Mechanical (MEMS)-based high G inertial shock sensor with a measurement range of 3,000-21,000 G is presented. The triggering mechanism is a combination of cantilever and spring structure. The design of the mechanism underwent a series of analyses. Simulation results indicated that a MEMS-based high G inertial shock sensor has a faster reaction time than conventional G inertial shock sensors that use a cantilever beam or spring mechanism. Furthermore, the MEMS-based high G inertial shock sensor is sufficiently robust to survive the impact encountered in high G application where most conventional G inertial shock sensors fail.