Browsing by Author "Chang, Yao-Wen"

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A Fast Route Towards Freestanding Single-Crystalline Oxide Thin Films by Using YBa(2)Cu(3)O(7-x)as a Sacrificial Layer
(2020-08-28)
Chang, Yao-Wen
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Wu, Ping-Chun
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Yi, Jhih-Bang
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Liu, Yu-Chen
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Chou, Yi
Researchers have long been seeking multifunctional materials that can be adopted for next-generation nanoelectronics, and which, hopefully, are compatible with current semiconductor processing for further integration. Along this vein, complex oxides have gained numerous attention due to their versatile functionalities. Despite the fact that unbounded potential of complex oxides has been examined over the past years, one of the major challenges lies in the direct integration of these functional oxides onto existing devices or targeted substrates that are inherently incompatible in terms of oxide growth. To fulfill this goal, freestanding processes have been proposed, in which wet etching of inserted sacrificial layers is regarded as one of the most efficient ways to obtain epitaxial high-quality thin films. In this study, we propose using an alternative oxide, YBa2Cu3O7(YCBO), as a sacrificial layer, which can be easily dissolved in light hydrochloric acid in a more efficient way, while protecting selected complex oxides intact. The high epitaxial quality of the selected complex oxide before and after freestanding process using YBCO as a sacrificial layer is comprehensively studied via a combination of atomic force microscopy, X-ray diffraction, transmission electron microscopy, and electrical transports. This approach enables direct integration of complex oxides with arbitrary substrates and devices and is expected to offer a faster route towards the development of low-dimensional quantum materials.
A Novel Hot-Electron Programming Method in a Buried Diffusion Bit-Line SONOS Memory by Utilizing Nonequilibrium Charge Transport
(2009-02-01)
Wang, Tahui
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Tang, Chun-Jung
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Li, C. -W.
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Lee, Chih Hsiung
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Ou, T. -F
We propose a new hot-electron programming method with a low drain-to-source voltage in a buried-diffusion (BD) bit-line SONOS memory array. In this method, channel electrons are preaccelerated in a cell preceding a program cell. For a small bit-line width, some energetic electrons will traverse an n(+) BD region and enter a program cell with residual energy due to nonequilibrium transport. Our measurement result shows that this residual energy can significantly enhance hot-electron programming efficiency even at a V(ds) of 2.5 V. The concept of this method is verified by means of a Monte Carlo analysis. Our study shows that this method is more effective as a bit-line width reduces.
Compositional Dependence of Phase Formation Mechanisms at the Interface Between Titanium and Calcia-Stabilized Zirconia at 1550 degrees C
(2010-11-01)
Chang, Yao-Wen
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Lin, Chien-Cheng
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材料科學與工程學系
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Department of Materials Science and Engineering
ZrO(2) samples with various CaO contents were fabricated by hot pressing, whereby CaO was dissolved by and/or reacted with ZrO(2) to form a solid solution and/or CaZr(4)O(9), respectively. After a reaction with Ti at 1550 degrees C for 6 h in argon, the interfacial microstructures were characterized using X-ray diffraction and analytical electron microscopy. Experimental results were very different from those found previously in the Y(2)O(3)-ZrO(2) system. The 5 mol% CaO-ZrO(2) sample was relatively stable due to the formation of a thin TiO layer acting as a diffusion barrier phase. However, alpha-Ti(O), beta'-Ti (Zr, O), and/or Ti(2)ZrO were found in 9 or 17 mol% CaO-ZrO(2) due to extensive interdiffusion of Ti, O, and Zr with a much thinner (beta'-Ti+alpha-Ti) layer in 17 mol% CaO-ZrO(2) than in 9 mol% CaO-ZrO(2). Because CaO was hardly dissolved into Ti, it fully remained in the residual ZrO(2), leading to the formation of spherical CaZrO(3) in 9 mol% CaO-ZrO(2) and columnar CaZrO(3) in 17 mol% CaO-ZrO(2). In the region far from the original interface, abundant intergranular alpha-Zr was formed in 5 or 9 mol% CaO-ZrO(2). Scattered alpha-Zr and CaZrO(3) were found in 17 mol% CaO-ZrO(2) because a high concentration of extrinsic oxygen vacancies, which were created by the substitution of Ca(+2) for Zr(+4), effectively retarded the reduction of zirconia.
Compositional Dependence of Phase Formation Mechanisms at the Interface Between Titanium and Calcia-Stabilized Zirconia at 1550 degrees C
(2010-11-01)
Chang, Yao-Wen
;
Lin, Chien-Cheng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
ZrO2 samples with various CaO contents were fabricated by hot pressing, whereby CaO was dissolved by and/or reacted with ZrO2 to form a solid solution and/or CaZr4O9, respectively. After a reaction with Ti at 1550 degrees C for 6 h in argon, the interfacial microstructures were characterized using X-ray diffraction and analytical electron microscopy. Experimental results were very different from those found previously in the Y2O3-ZrO2 system. The 5 mol% CaO-ZrO2 sample was relatively stable due to the formation of a thin TiO layer acting as a diffusion barrier phase. However, alpha-Ti(O), beta'-Ti (Zr, O), and/or Ti2ZrO were found in 9 or 17 mol% CaO-ZrO2 due to extensive interdiffusion of Ti, O, and Zr with a much thinner (beta'-Ti+alpha-Ti) layer in 17 mol% CaO-ZrO2 than in 9 mol% CaO-ZrO2. Because CaO was hardly dissolved into Ti, it fully remained in the residual ZrO2, leading to the formation of spherical CaZrO3 in 9 mol% CaO-ZrO2 and columnar CaZrO3 in 17 mol% CaO-ZrO2. In the region far from the original interface, abundant intergranular alpha-Zr was formed in 5 or 9 mol% CaO-ZrO2. Scattered alpha-Zr and CaZrO3 were found in 17 mol% CaO-ZrO2 because a high concentration of extrinsic oxygen vacancies, which were created by the substitution of Ca+2 for Zr+4, effectively retarded the reduction of zirconia.
DDX3 Represses Stemness by Epigenetically Modulating Tumor-suppressive miRNAs in Hepatocellular Carcinoma
(2016-06-27)
Li, Hao-Kang
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Mai, Ru-Tsun
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Huang, Hsien-Da
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Chou, Chih-Hung
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Chang, Yi-An
Studies indicate that the presence of cancer stem cells (CSCs) is responsible for poor prognosis of hepatocellular carcinoma (HCC) patients. In this study, the functional role of DDX3 in regulation of hepatic CSCs was investigated. Our results demonstrated that reduced DDX3 expression was not only inversely associated with tumor grade, but also predicted poor prognosis of HCC patients. Knockdown of DDX3 in HCC cell line HepG2 induced stemness gene signature followed by occurrence of self-renewal, chemoreisistance, EMT, migration as well as CSC expansion, and most importantly, DDX3 knockdown promotes tumorigenesis. Moreover, we found positive correlations between DDX3 level and expressions of tumor-suppressive miR-200b, miR-200c, miR-122 and miR-145, but not miR-10b and miR-519a, implying their involvement in DDX3 knockdown-induced CSC phenotypes. In addition, DDX3 reduction promoted up-regulation of DNA methyltransferase 3A (DNMT3A), while neither DNMT3B nor DNMT1 expression was affected. Enriched DNMT3A binding along with hypermethylation on promoters of these tumor-suppressive miRNAs reflected their transcriptional repressions in DDX3-knockdown cells. Furthermore, individual restoration of these tumor-suppressive miRNAs represses DDX3 knockdown-induced CSC phenotypes. In conclusion, our study suggested that DDX3 prevents generation of CSCs through epigenetically regulating a subset of tumor-suppressive miRNAs expressions, which strengthens tumor suppressor role of DDX3 in HCC.
ECO Optimization Using Metal-Configurable Gate-Array Spare Cells
(2013-11-01)
Chang, Hua-Yu
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Hui-Ru, Iris
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Chang, Yao-Wen
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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
Due to the rapidly increasing design complexity in modern IC designs, metal-only engineering change order (ECO) becomes inevitable to achieve design closure with a low respin cost. Traditionally, preplaced redundant standard cells are regarded as spare cells. However, these cells are limited by predefined functionalities and locations, and they always consume leakage power despite their inputs being tied off. To overcome the inflexibility and power overhead, a new type of spare cells, called metal-configurable gate-array spare cells, are introduced. In this paper, we address a new ECO problem, which performs design changes using metal-configurable gate-array spare cells. We first study the properties of this new ECO problem and propose a new cost metric, aliveness, to model the capability of a spare gate array. Based on aliveness and routability, we then develop two ECO optimization frameworks, one for timing ECO and the other for functional ECO. Experimental results show that our approach delivers superior efficiency and effectiveness.
Effect of yttria on interfacial reactions between titanium melt and hot-pressed yttria/zirconia composites at 1700 degrees C
(2008-07-01)
Lin, Chien-Cheng
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Chang, Yao-Wen
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Lin, Kun-Lin
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Lin, Kun-Fung
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材料科學與工程學系
Various Y(2)O(3)/ZrO(2) samples were fabricated by hot pressing, whereby Y(2)O(3) was mutually dissolved or reacted with ZrO(2) as a solid solution or Zr(3)Y(4)O(12). Hot-pressed samples were allowed to react with Ti melt at 1700 degrees C for 10 min in argon. Microstructural characterization was conducted using X-ray diffraction and analytical electron microscopy. The Y(2)O(3)/ZrO(2) samples became more stable with increasing Y(2)O(3) because Y(2)O(3) was hardly reacted and dissolved with Ti melt. The incorporation of more than 30 vol% Y(2)O(3) could effectively suppress the reactions in the Ti side, where only a very small amount of alpha-Ti and beta'-Ti was found. When ZrO(2) was dissolved into Ti on the zirconia side near the original interfaces, Y(2)O(3) reprecipitated in the samples containing 30%-70 vol% Y(2)O(3), because the solubility of Y(2)O(3) in Ti was very low. In the region far from the original interface, alpha-Zr, Y(2)O(3), and/or residual Zr(3)Y(4)O(12) were found in the samples containing more than 50 vol% Y(2)O(3) and the amount of alpha-Zr decreased with increasing Y(2)O(3).
Functional ECO Using Metal-Configurable Gate-Array Spare Cells
(2014)
Chang, Hua-Yu
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Jiang, Iris Hui-Ru
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Chang, Yao-Wen
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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
Metal-configarable gate-array spare cells, which have versatile functionality, are developed to overcome the inflexibility of standard spare cells used in conventional metal-only engineering change order (ECO). In this paper, we focus on functional ECO optimization using the new type of spare cells to fully exploit its strength. We observe that this functional LCD problem has the nature of dynamic logical and physical costs for at spare gate arrays. Unlike existing functional E0 works, which perform technology snapping based on ECO patches, we perform reverse mapping from spare gate arrays to handle these dynamic costs. We devise a spare array relation graph to record geometrical adjacency among spare gate arrays and interleave with the and-inverter network of ECO patches. To avoid redundant traversal and monitor the dynamic costs, we adopt A* search to simultaneously traverse and imp between the logical LCD network and the physical spare array relation graph.
IEEE standard 1500 compatible interconnect diagnosis for delay and crosstalk faults
(2006-11-01)
Li, Katherine Shu-Min
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Su, Chauchin
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Chang, Yao-Wen
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Lee, Chung-Len
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Chen, Jwu E.
An interconnect diagnosis scheme based on the oscillation ring (OR) test methodology for systems-on-chip (SOC) design with heterogeneous cores is proposed. In addition to traditional stuck-at and open faults, the OR test can also detect and diagnose important interconnect faults such as delay faults and crosstalk glitches. The large number of test rings in the SOC design, however, significantly complicates the interconnect diagnosis problem. In this paper, the diagnosability of an interconnect structure is first analyzed then a fast diagnosability checking algorithm and an efficient diagnosis ring generation algorithm are proposed. It is shown in this paper that the generation algorithm achieves the maximum diagnosability for any interconnect. Two optimization techniques are also proposed, an adaptive and a concurrent diagnosis method, to improve the efficiency and effectiveness of interconnect diagnosis. Experiments on the MCNC benchmark circuits show the effectiveness of the proposed diagnosis algorithms. In all experiments, the method achieves 100% fault detection coverage and the optimal interconnect diagnosis resolution.
IEEE standard 1500 compatible interconnect diagnosis for delay and crosstalk faults
(2006-01-01)
Li, Katherine Shu-Min
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Chang, Yao-Wen
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Su, Chauchin
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Lee, Chung-Len
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Chen, Jwu E.
We propose an interconnect diagnosis scheme based on Oscillation Ring test methodology for SOC design with heterogeneous cores. The target fault models are delay faults and crosstalk glitches. We analyze the diagnosability of an interconnect structure and propose a fast diagnosability checking algorithm and an efficient diagnosis ring generation algorithm which achieves the optimal diagnosability. Two optimization techniques improve the efficiency and effectiveness of interconnect diagnosis. In all experiments, our method achieves 100% fault coverage and the optimal diagnosis resolution.
Inactivation Effect of Colletotrichum Gloeosporioides by Long-Lived Chemical Species Using Atmospheric-Pressure Corona Plasma-Activated Water
(2019-02-01)
Wu, Mu-Chien
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Liu, Chih-Tung
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Chiang, Chun-Yi
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Lin, Yi-Jia
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Lin, Ying-Hong
In this paper, atmospheric-pressure air and oxygen corona plasma jets under water surface have been used to generate plasma-activated water (PAW) to inactivate colletotrichum gloeosporioides (C. gloeosporioides) suspension. The atmospheric-pressure plasma jets in the water were characterized by measuring: 1) the electrical and optical properties for evaluating the plasma efficiency and 2) the physicochemical properties of PAW, including pH value, oxidation-reduction potential value, and the concentration of hydrogen peroxide, nitrite, and ozone. The aim of this paper is to investigate the effects of long-lived reactive oxygen and nitrogen species (RONS) and environmental factor (acidity) in PAW on fungicidal property. The results of antifungal activity show that the inactivation rate of C. gloeosporioides is higher using air-PAW than oxygen-PAW, and increases with increasing reaction time when preparation time of PAW is fixed as 30 min. This correlates well with measurements of the aqueous-phase long-lived RONS concentration such as nitrate and ozone, suggesting these species play crucial roles in the inactivation process.
Multilevel full-chip routing with testability and yield enhancement
(2007-09-01)
Li, Katherine Shu-Min
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Chang, Yao-Wen
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Lee, Chung-Len
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Sul, Chauchin
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Chen, Jwu E.
We propose a multilevel full-chip routing algorithm that improves testability and diagnosability, manufacturability, and signal integrity for yield enhancement. Two major issues are addressed. 1) The oscillation ring test (ORT) and its diagnosis scheme for interconnects based on the popular IEEE Standard 1500 are integrated into the multilevel routing framework to achieve testability enhancement. We augment the traditional multilevel framework of coarsening and uncoarsening by introducing a preprocessing stage that analyzes the interconnect structure for better resource estimation before the coarsening stage, and a final stage after uncoarsening that improves testability to achieve 100% interconnect fault coverage and maximal diagnosability. 2) We present a heuristic to reduce routing congestion to optimize the multiple-fault probability, chemical-mechanical polishing- and optical proximity correction-induced manufacturability, and crosstalk effects, for yield improvement. Experimental results on the Microelectronics Center for North Carolina benchmark circuits show that the proposed ORT method achieves 100% fault coverage and the optimal diagnosis resolution for interconnects. Further, the multilevel routing algorithm effectively balances the routing density to achieve 100% routing completion.
RLC coupling-aware simulation and on-chip bus encoding for delay reduction
(2006-10-01)
Tu, Shang-Wei
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Chang, Yao-Wen
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Jou, Jing-Yang
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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
This paper shows. that the worst case switching pattern that incurs the longest bus delay While considering the RLC effect is quite different from that while considering the RC effect alone. It implies that the existing encoding schemes based on the RC model may not improve or possibly worsen the delay when the inductance effects become dominant. A bus-invert method is also proposed to reduce the on-chip bus delay based on the RLC model. Simulation results show that the proposed encoding scheme significantly reduces the worst case coupling delay of the inductance-dominated buses.
Routing for Manufacturability and Reliability
(2009)
Chen, Huang-Yu
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Chang, Yao-Wen
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交大名義發表
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National Chiao Tung University
As IC process geometries scale down to the nanometer territory, industry faces severe challenges of manufacturing limitations. To guarantee high yield and reliability, routing for manufacturability and reliability has played a pivotal role in resolution and thus yield enhancement for the imperfect manufacturing process. In this article, we introduce major routing challenges arising from nanometer process, survey key existing techniques for handling the challenges, and provide some future research directions in routing for manufacturability and reliability.
Simultaneous Functional and Timing ECO
(2011-01-01)
Chang, Hua-Yu
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Jiang, Iris Hui-Ru
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Chang, Yao-Wen
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Metal-only ECO is prevalent at design houses to perform incremental design changes to resolve last found functional and/or timing failures. However, it is hard to perform mixed functional and timing changes manually. Prior endeavors focus on functional or timing ECO alone, but we observe that separating them may fail to fix all timing violations. Consequently, this paper presents the first work to perform simultaneous functional and timing ECO. We use an augmented bipartite graph to model both types of ECO. In addition, through comprehensive constant insertion and bridging, the functional capability of each spare cell is enhanced, thus facilitating spare cell selection. Experimental results show that our simultaneous functional and timing ECO engine can successfully resolve mixed functional and timing ECO that is unsolvable by the sequential scheme. Moreover, our engine outperforms the state-of-the-art works for timing ECO with a 117X speedup, and for functional ECO with 6-15% wirelength reductions.
Timing ECO Optimization Via Bezier Curve Smoothing and Fixability Identification
(2012-12-01)
Chang, Hua-Yu
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Jiang, Iris Hui-Ru
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Chang, Yao-Wen
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Due to the rapidly increasing design complexity in modern integrated circuit design, more and more timing failures are detected at late stages. Without deferring time-to-market, metal-only engineering change order (ECO) is an economical technique to correct these late-found failures. Typically, a design might need to undergo many ECO runs in design houses; consequently, the usage of spare cells for ECO is of significant importance. In this paper, we aim at timing ECO by using as few spare cells as possible. We observe that a path with good timing is desired to be geometrically smooth. Unlike negative slack and gate delay used in most prior work, we propose a new metric of timing criticality, fixability, by considering the smoothness of timing violating paths. To measure the smoothness of a path, we use the Bezier curve as the golden path. Furthermore, in order to concurrently fix timing violations, we derive a propagation property to divide violating paths into independent segments. Based on Bezier curve smoothing, fixability identification, and the propagation property, we develop an efficient algorithm to fix timing violations. Experimental results show that we can effectively resolve all timing violations with significant speedups over the state-of-the-art works.
Timing ECO Optimization via Bezier Curve Smoothing and Fixability Identification
(2011)
Chang, Hua-Yu
;
Jiang, Iris Hui-Ru
;
Chang, Yao-Wen
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Due to the rapidly increasing design complexity in modern IC design, more and more timing failures are detected at late stages. Without deferring time-to-market, metal-only ECO is an economical technique to correct these late-found failures. Typically, a design undergoes many ECO runs in design houses; the usage of spare cells is of significant importance. Hence, in this paper, we aim at timing ECO using the least number of spare cells. We observe that a path with good timing is desired to be geometrically smooth. Different from negative slack and gate delay used in most of prior work, we propose a new metric of timing criticality-fixability-considering the smoothness of critical paths. To measure the smoothness of a path, we use Bezier curve as the golden path. Furthermore, in order to concurrently fix timing violations, we derive the dominance property to divide violated paths into independent segments. Based on Bezier curve smoothing, fixability identification, and the dominance property, we develop an efficient algorithm to fix violations. Compared with the state-of-the-art works, experimental results show that our algorithm not only effectively resolves all timing violations with few spare cells but also achieves 22.8X and 42.6X speedups.
Ultrafast Giant Photostriction of Epitaxial Strontium Iridate Film with Superior Endurance
(2018-12-01)
Yang, Jan-Chi
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Liou, Yi-De
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Tzeng, Wen-Yen
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Liu, Heng-Jui
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Chang, Yao-Wen
Photostriction, optical stimulus driven mechanical deformation in materials, provides a solution toward next-generation technology. Here, the giant photostriction (similar to 2% change of lattice) of epitaxial strontium iridate (SrIrO3) films under illumination at room temperature is revealed via power-dependent Raman scattering, which is significantly larger as compared to conventional inorganic materials. The time scale and mechanism of this giant photostriction in SrIrO3 are further studied through time-resolved transient reflectivity measurements. The main mechanism is determined to be the electron-phonon coupling. In addition, we find that such an exotic behavior happens within few picoseconds and remains up to 107 cyclic on/off operations. The observation of giant photostriction in SrIrO3 films with superior endurance promises the advance of shape responsive solids that are sensitive to environmental stimuli, which could be widely utilized for multifunctional optoelectronics and optomechanical devices.