Browsing by Author "Yang, Po-Chun"

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Influence of forming process on resistance switching characteristics of In2O3/SiO2 bi-layer
(2013-01-15)
Huang, Jheng-Jie
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Chang, Ting-Chang
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Yang, Po-Chun
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Chen, Yu-Ting
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Tseng, Hsueh-Chih
In this study, we fabricated and analyzed resistance switching characteristics for resistance random access memory (RRAM) in a Pt/In2O3/SiO2/TiN structure. By applying opposing electric fields to performa soft breakdown of the In2O3/SiO2 insulating bi-layer, different switching behaviors are exhibited. When positive forming voltage was applied to the TiN electrode to soft breakdown the device, the resistance switching behavior was dominated by the bipolar mode. However, the negative voltage forming process exhibited both unipolar switching characteristics in addition to a bipolar switch mode. In order to analyze the composition of the conduction path and resistance switching mechanism, resistance value trends versus temperature was extracted and showed that the conduction paths of bipolar and unipolar modes are dominated by oxygen vacancies and metallic filament, respectively. Hence, metallic filament was considered to be formed by the migration of indium ions because the unipolar characteristic was only present during negative bias forming condition. (c) 2012 Elsevier B.V. All rights reserved.
Influence of molybdenum doping on the switching characteristic in silicon oxide-based resistive switching memory
(2013-01-28)
Chen, Yu-Ting
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Chang, Ting-Chang
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Huang, Jheng-Jie
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Tseng, Hsueh-Chih
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Yang, Po-Chun
This report compares Mo-doped and undoped SiO2 thin films of a similar thickness as well as MoOx. The Mo-doped SiO2 film exhibited switching behavior after the forming process, unlike the undoped SiO2 film. Through material analyses, a self-assembled layer is observed in the Mo-doped SiO2 film. Due to the formation of this layer, the thickness required to be broken down is effectively reduced. Subsequently, the occurrence of the switching behavior in the thinner SiO2 film further confirmed the supposition. A comparison of the two switching behaviors shows that SiO2 dominates the switching characteristic of the Mo-doped SiO2. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790277]
Influence of Oxygen Concentration on Resistance Switching Characteristics of Gallium Oxide
(2012-10-01)
Huang, Jheng-Jie
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Chang, Ting-Chang
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Yang, Jyun-Bao
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Chen, Shih-Ching
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Yang, Po-Chun
In this letter, we fabricated resistance random access memory in a Pt/GaOx/TiN structure with a bipolar resistance switching characteristic and a bistable resistance ratio of about two orders by I-V sweeping. In order to increase the oxygen ion quantity in the gallium oxide layer, the proposed sample was sputtered in a mixed ambient of Ar and oxygen, and the resistance ratio was enhanced by 2.5 orders. In addition to the resistance ratio, set voltage distribution statistics show that the stability of gallium oxide sputtered in mixed Ar and oxygen gas was better than standard Ar-only sample.
Investigating the improvement of resistive switching trends after post-forming negative bias stress treatment
(2011-09-26)
Tseng, Hsueh-Chih
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Chang, Ting-Chang
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Huang, Jheng-Jie
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Yang, Po-Chun
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Chen, Yu-Ting
This paper investigates the improvement of resistive switching trends after post-forming negative bias stress treatment of a Pt/Yb(2)O(3)/TiN device that has undergone positive bias forming process for activation. After the treatment, characteristics of the conductive filament, such as the temperature dependence of resistivity and transition mechanism, undergo changes. Furthermore, this treatment causes the conductive filament to transform from being primarily composed of vacancies to being metallic Yb dominant, which not only reduces operation voltages such as V(set) and V(reset) but also improves the on/off ratio. In reliability tests, the device has stable retention. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3645004]
Multimedia short message template application system and broadcast system, multimedia short message template applying method and broadcast method
(2007-06-14)
Chen, Deng-Jyi
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Hung, Chi-Chang
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Yang, Po-Chun
A multimedia short message template application system and a broadcast system, a multimedia short message template applying method and a broadcast method are disclosed. The multimedia short message template application system comprises a multimedia object, a multimedia database, a template database and an applying unit. The multimedia object includes an object content attribute and an object motion attribute. The object motion attribute includes an interaction function. The multimedia database is composed of a multimedia data. The template database is composed of short message templates. Any short message template includes a combination arrangement of a multimedia object. A corresponding short message template is found by the applying unit from the template database based on the selection chosen by a user. A corresponding multimedia data is then found from the multimedia database based on the selection chosen by the user again. Lastly, the corresponding multimedia data is loaded into the object content attribute of the short message template within the multimedia object to make a multimedia short message.
Rank Analysis of Parity-Check Matrices for Quasi-Cyclic LDPC Codes
(2018-01-01)
Yang, Po-Chun
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Wang, Chung-Hsuan
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Chao, Chi-chao
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電信工程研究所
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Institute of Communications Engineering
Quasi-cyclic low-density parity-check (QC-LDPC) codes are an important class of LDPC codes which can be encoded and decoded with low complexity and suitable for many applications. As the code dimension, which describes the number of protected information bits, is equal to the code length minus the rank of the parity-check matrix and the parity-check matrix for QC-LDPC codes is usually not full-rank, determining the rank of the parity-check matrix is of essential importance. In this paper, we study the rank of the parity-check matrix for QC-LDPC codes based on the associated polynomials for circulant matrices. A formula for the rank of the parity-check matrix with only one row-block is first derived. We then extend the result to matrices with two, three, or more row-blocks. Some bounds are also presented for matrices with arbitrary numbers of row-blocks. Furthermore, the exact rank is determined for a class of algebraically constructed parity-check matrices.
Resistive switching characteristics of gallium oxide for nonvolatile memory application
(2013-02-01)
Yang, Jyun-Bao
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Chang, Ting-Chang
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Huang, Jheng-Jie
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Chen, Shih-Ching
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Yang, Po-Chun
This study investigates bipolar resistance switching memory in a fabricated Pt/GaOx/TiN device. Gallium oxide sputtered in ambient Ar shows a change in resistance ratio of two orders of magnitude. The enhancement of resistance ratio is also observed in the gallium oxide layer when deposited in ambient Ar/O-2. The X-ray photoelectron spectroscopy analysis shows that this gallium oxide in ambient Ar/O-2 can reduce the number of defects and enhance the stability of switching behavior. An analysis of current transport mechanism in the high resistance state indicates that the larger effective thickness can be attributed to the higher oxygen concentration, and can increase the resistance value of the high resistance state. (C) 2012 Elsevier B.V. All rights reserved.
Resistive switching characteristics of ytterbium oxide thin film for nonvolatile memory application
(2011-12-30)
Tseng, Hsueh-Chih
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Chang, Ting-Chang
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Huang, Jheng-Jie
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Chen, Yu-Ting
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Yang, Po-Chun
This paper studies the effects of both the positive and negative forming processes on the resistive switching characteristics of a Pt/Yb(2)O(3)/TiN RRAM device. The polarity of the forming process can determine the transition mechanism, either bipolar or unipolar. Bipolar behavior exists after the positive forming process, while unipolar behavior exists after the negative forming process. Furthermore, the bipolar switching characteristics of the Pt/Yb(2)O(3)/TiN device can be affected by using a reverse polarity forming treatment, which not only reduces the set and reset voltage, but also improves the on/off ratio. Crown Copyright (C) 2011 Published by Elsevier B. V. All rights reserved.
The effect of pre-aging on the electromigration of flip-chip SnAg solder joints
(2008-06-01)
Yang, Po-Chun
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Kuo, Chien-Chih
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Chen, Chih
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材料科學與工程學系
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Department of Materials Science and Engineering
The effect of pre-aging on electromigration is investigated in this study using flip-chip SnAg solder joints. The solder joints were pre-aged at 170 degrees C for 1 h, 3 h, 5 h, 10 h, 25 h, and 50 h, and then they were subjected to electromigration tests of 0.9 A at 150 degrees C. It was found that the average failure time increased about three times when the joints were pre-aged for 3 h to 25 h. But it decreased when the joints were over-aged. It is proposed that the major contributor to the prolonged failure time may be the densification of the nickel and copper under-bump metallization (UBM) and the solder due to the aging treatment. The pre-aging treatment at 170 degrees C may stabilize the microstructure of the solder. The vacancies in the solder were annihilated during the heat treatment, causing a slower diffusion rate. In addition, the UBM structure became denser after the pre-aging process. Thus, the denser UBM structure may lead to slower consumption rates of the nickel and copper layers, resulting in the enhancement of electromigration resistance.