Browsing by Author "Chang, K. M."

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Bipolar resistive switching characteristics of Gd2O3 thin film structure
(2011)
Chang, K. M.
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Tzeng, W. H.
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Liu, K. C.
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Chan, Y. C.
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Kuo, C. C.
The resistive switching (RS) behavior of the Ti/Gd2O3/Pt capacitor structure is fabricated and discussed in this paper. The switching characteristics operated under positive bias exhibits stable switching properties with a condensed voltage and resistance values dispersion, while the switching characteristics becomes unstable and large fluctuation on switching parameters under the negative bias operation. We suggest that the anode electrode plays an important role to the switching characteristics, and might be the causes of the asymmetry of the I-V curves between positive and negative operation. Constant voltage stress measurement is also tested to reveal the switching mechanism of the Gd2O3 film, and the switching mechanism is mainly based on the applied voltage and thermal Joule heat.
Excellent combination of strength and ductility in an Fe-9Al-28Mn-1.8C alloy
(2010-07-01)
Chang, K. M.
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Chao, C. G.
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Liu, T. F.
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材料科學與工程學系
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Department of Materials Science and Engineering
An optimal aging at 450 degrees C resulting in the subject alloy possessing a high yield strength of 1383 MPa with 32.5% elongation. With almost equivalent elongation, the yield strength was about 28% higher than that of FeAlMnC (C <= 1.3 wt.%) alloys after solution heat-treatment or controlled-rolling followed by optimal aging. Additionally, due to pre-existing fine (Fe,Mn)(3)AlC carbides in as-quenched alloy, the aging time required for attaining the optimal combination of strength and ductility was much less than that for FeAlMnC (C <= 1.3 wt.%) alloys. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Field Dependence of Porous Low-k Dielectric Breakdown as Revealed by the Effects of Line Edge Roughness on Failure Distributions
(2011-03-01)
Lee, S. C.
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Oates, A. S.
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Chang, K. M.
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
We investigate the electric field (E) dependence of the breakdown of porous low-k dielectrics by measuring the changes in the failure time distribution resulting from the presence of line edge roughness. We show that the Weibull beta increases with decreasing field, clearly demonstrating that dielectric breakdown does not exhibit 1/E or E(-n) characteristics.
Flow Rate's Influence on Low Temperature Silicon Oxide Deposited by Atmospheric Pressure Plasma Jet for Organic Thin Film Transistor Application
(2010)
Chang, K. M.
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Huang, S. S.
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Cheng, C. H.
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Low temperature processes and high quality gate insulator are very important for organic thin film transistors (OTFTs). We utilized atmospheric pressure plasma jet (APPJ) to deposit silicon oxide as gate insulator of OTFTs at low temperature. We found carrier gas's flow rate would influence the deposition mechanism which lead to influence surface roughness and film quality. Leakage current density of our proposed silicon oxide was about 2.53E-8 A/cm(2) at 0.5 MV/cm. Our proposed OTFTs shows a low subthreshold swing of only 700 mV/dec., a low threshold voltage of -0.8 V, a low operation voltage of -2 V. The low-voltage OTFTs would reduce the power consummation of flexible display.
Modulation of the Electrical Characteristics of HfOx/TiN RRAM Devices through the Top Electrode Metal
(2010)
Chang, K. M.
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Tzeng, W. H.
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Liu, K. C.
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Lai, W. R.
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電子工程學系及電子研究所
The effect of the top electrode on switching characteristics of a HfOx/TiN structure was investigated. From the electrical conduction analysis, the conduction mechanism between Pt and Ti was found to be quite different. A potential barrier formed in the Pt/HfOx interface showing the Fowler-Nordheim tunneling at high bias. However, it was not observed in the Ti/HfOx structure. Reactive metal Ti interacted with the underlying HfOx film leading to destruction of the barrier height. As such, the device lost the ability to operate at the mu A compliance current range. Pt/HfOx demonstrated the merit of a large resistance ratio and a low operation current (Ireset = 20 mu A). However, Ti/HfOx exhibited better voltage dispersion at the low resistance state (0.5V dispersion). The electrode plays a dominant role in determining the electrical characteristics of a resistive random access memory (RRAM) device. Therefore, choosing an adequate electrode for RRAM is an important consideration.