Browsing by Author "Yao, Yeong-Der"

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A 2-bit/cell, maskless, self-aligned resistance memory with high thermal stability
(2007)
He, ChiaHua
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Lee, Ming-Daou
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Pan, Chen-Ling
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Lai, Erb-Kun
;
Yao, Yeong-Der
We report the first demonstration of a multilevel cell (MLC) resistance device using a self-aligned WO, film prepared by plasma oxidation. The 2-bit/cell operation is achieved by applying a series of 1.5V programming pulses. The device shows high thermal stability and good data retention. The resistance change can be attributed to variable-range hopping and Ohmic transport mechanisms. This device has the potential for future low-voltage, 3-dimentioanl nonvolatile memory with multiple bits per layer. In addition, no additional mask is needed to form the self-aligned device.
Axial Vibration Study of a Mobile Fan Motor
(2010-06-01)
Wang, Chien-Chang
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Yao, Yeong-Der
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Liang, Kun-Yi
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Huang, Chung-Chun
;
Chang, Yu-Choung
A method observing both radial and axial vibrations of time domain and frequency spectrum was studied to investigate the axial load effect of a flat-type brushless dc fan motor operating with and without the rated axial thrust force. When the developed small motor does not exhibit an intrinsically excited unbalanced magnetic force (UMF), the axial force leads to a minor contribution to the growth of the axial vibration. However, when the UMF is intrinsically excited, the preload can enormously decrease the undesired axial vibration. The ratio of the axial vibration of the prototype with the asymmetric magnetic sheet to the one without the sheet is experimentally observed around 55 percent. It demonstrates that axial load plays an effective and crucial factor in controlling the axial vibration of the mobile fan motor.
CMOS Fully Compatible Embedded Non-Volatile Memory System With TiO(2)-SiO(2) Hybrid Resistive-Switching Material
(2011-03-01)
Lee, Ming-Daou
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Ho, ChiaHua
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Yao, Yeong-Der
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材料科學與工程學系
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Department of Materials Science and Engineering
We demonstrate a non-volatile CMOS fully compatible embedded memory cell with a hybrid resistive switching material, TiO(2)-SiO(2), in a 0.18 mu m node CMOS process. Both voltage-and temperature-dependent transports indicate that a Schottky-type resistance switching model dominates the TiO(2) based transition-metal-oxide resistive random access memory (TMO-RRAM) system. Data retention is improved by inserting a very thin SiO(2) layer between the bottom electrode and TiO(2) film to enhance the Schottky barrier height, while maintaining TiO(2) based RRAM characteristics.
CMOS Fully Compatible Embedded Non-Volatile Memory System With TiO2-SiO2 Hybrid Resistive-Switching Material
(2011-03-01)
Lee, Ming-Daou
;
Ho, ChiaHua
;
Yao, Yeong-Der
;
材料科學與工程學系
;
Department of Materials Science and Engineering
We demonstrate a non-volatile CMOS fully compatible embedded memory cell with a hybrid resistive switching material, TiO2-SiO2, in a 0.18 mu m node CMOS process. Both voltage-and temperature-dependent transports indicate that a Schottky-type resistance switching model dominates the TiO2 based transition-metal-oxide resistive random access memory (TMO-RRAM) system. Data retention is improved by inserting a very thin SiO2 layer between the bottom electrode and TiO2 film to enhance the Schottky barrier height, while maintaining TiO2 based RRAM characteristics.
Development of a miniature fan motor
(2012-04-01)
Wang, Chien-Chang
;
Yao, Yeong-Der
;
Liang, Kun-Yi
;
Huang, Chung-Chun
;
Chang, Yu-Choung
A novel compact axial flux fan motor was developed. Such a micromotor could be a potential candidate for using as the cooling solution for the next generation mobile devices, for example, smart phones and pico-projectors. The key parameters of the motor, such as back electromotive force, cogging torque, and axial preload are predicted using finite element method. In addition, new approaches are proposed to measure these items, and the corresponding experimental results are in good agreement with the simulated one. Moreover, the undesired vibration harmonic is successfully suppressed, and the fan motor represents a high static pressure and air flow rate. (C) 2012 American Institute of Physics. [doi:10.1063/1.3675993]
Effect of oxygen concentration on characteristics of NiOx-based resistance random access memory
(2007-02-01)
Lee, Ming-Daou
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Ho, Chia-Hua
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Lo, Chi-Kuen
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Peng, Tai-Yen
;
Yao, Yeong-Der
The resistance bistability and the switching effect has been systematically studied in nickel oxide films with variable oxygen concentrations. Both the switching bias voltage and the resistance ratio of RESET to SET were found to be strongly concentration dependent. Meanwhile, the electrical characteristics can be exactly examined by an Schottky emission. By means of mathematical fitting, the resistance bistability seems to be related to the alternating of dielectric constant and the barrier height. Furthermore, the room temperature cycle endurance with a distinguishable operation window was found to exceed 800. This indicates that the nickel oxide has the potential to be a promising material on resistance random access memory.
Magnetoimpedance behavior and its equivalent circuit analysis of Co/Cu/Co/Py pseudo-spin-valve with a nano-oxide layer
(2009-02-01)
Chien, Wei-Chih
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Yao, Yeong-Der
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Wu, Jiann-Kuo
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Lo, Chi-Kuen
;
Hung, Ruei-Feng
Magnetoimpedance behaviors and thermal effects of a Co/Cu/Co/Py pseudo-spin-valve (PSV) with a nano-oxide layer (NOL) were studied. The PSV can be regarded as a combination of resistances, inductances, and capacitances. In addition, equivalent circuit theory can be used to analyze the ac behavior of this system. The imaginary part of the magnetoimpedance (magnetoreactance) ratio is more than 1700% at the resonance frequency (f(r))=476 kHz at room temperature (R(T)). The dc magnetoresistance (MR) ratio decreases as the annealing temperature increases because the NOL is formed at the interface between the spacer and the magnetic layer. The NOL deteriorates the differential spin scattering and reduces the dc MR ratio. Impedance spectroscopy was utilized to analyze the capacitance effect from NOL after annealing. The effective capacitance of the PSV was 21.8 nF at R(T) and changed to 11.8 nF after annealing at 200 degrees C. The useful equivalent capacitor circuit not only is a nondestructive measurement technology but can also explain the experimental results and prove the formation of the NOL.
Micro-magnetic suspension motor design for miniature optical drive
(2006-07-01)
Wang, Chien-Chang
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Yao, Yeong-Der
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Liu, Chien-Sheng
;
Cheng, Lung-Yu
;
交大名義發表
The main purpose of this study is to develop a low vibration micromotor applied in a miniature optical drive. To minimize the micromotor vibration, passive magnetic suspensidn technology has been used. The magnetic forces between the permanent magnets are estimated using the finite element method; the stable zone of operation of the motor developed was determined. A new micromotor with 62% of the radial vibration of the conventional micro-ball-bearing motor has been successfully developed. In addition, the new motor demonstrates lower friction torque loss.
Tungsten Oxide Resistive Memory Using Rapid Thermal Oxidation of Tungsten Plugs
(2010)
Lai, Erh-Kun
;
Chien, Wei-Chih
;
Chen, Yi-Chou
;
Hong, Tian-Jue
;
Lin, Yu-Yu
A complementary metal oxide semiconductor (CMOS)-compatible WO(x) based resistive memory has been developed. The WO(x) memory layer is made from rapid thermal oxidation of W plugs. The device performs excellent electrical properties. The switching speed is extremely fast (similar to 2 ns) and the programming voltage (< 1: 4 V) is low. For single-level cell (SLC) operation, the device shows a large resistance window, and 10(8)-cycle endurance. For multi-level cell (MLC) operation, it demonstrates 2-bit/cell storage with the endurance up to 10000 times. The rapid thermal oxidation (RTO) WO(x) resistance random access memory (RRAM) is very promising for both high-density and embedded memory applications. (C) 2010 The Japan Society of Applied Physics