Browsing by Author "Chen, SJ"

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A new physical and quantitative width dependent hot carrier model for shallow-trench-isolated CMOS devices
(2001)
Chung, SS
;
Chen, SJ
;
Yang, WJ
;
Yang, JJ
;
電子工程學系及電子研究所
In this paper, we present new results on the width dependent hot-carrier (HC) degradation for shallow-trench-isolated (STI) CMOS devices. Experimental data shows that the drain current degradation is enhanced for a reducing gate width. New models and mechanisms are proposed to explain the width dependent degradation for both n-channel and p-channel MOSFET's, where new monitors are developed for both types of devices respectively. In fi-MOSFET's, the interface state generation at the STI-edge is enhanced for narrow width device. However, for p-MOSFET's, a two-dimensional channel shortening model is introduced. The channel shortening induced oxide damage is the dominant mechanism for the drain current degradation. Both are found to be strongly related to the mechanical stress on the border of the trench. This is a very crucial issue for the present and future CMOS ULSI using STI technologies.
A novel and direct determination of the interface traps in sub-100nm CMOS devices with direct tunneling regime (12 similar to 16A) gate oxide
(2002)
Chung, SS
;
Chen, SJ
;
Yang, CK
;
Cheng, SM
;
Lin, SH
For the first time, an improved charge pumping (CP) method has been implemented for direct determination of the interface traps in ultra-short gate length CMOS devices with ultra-thin gate oxide in the direct tunneling regime. The leakage current in a 12-16A gate oxide can be removed from the measured CP current, which enables accurate determination of the interface traps. This method has, been demonstrated successfully for various RTNO grown and RPN treated oxide CMOS devices with very thin gate oxide. Moreover, it can be used as a good monitor of ultra-thin gate oxide process and the evaluations of device reliabilities in relating to the interface trap generation.
An accurate hot carrier reliability monitor for deep-submicron shallow S/D junction thin gate oxide n-MOSFET's
(1999)
Chung, SS
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Chen, SJ
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Yih, CM
;
Yang, WJ
;
Chao, TS
In this paper, an accurate criterion has been proposed for reliability evaluation of state-of-the-art deep-submicron S/D extension n-MOSFET's. A new monitor for HC reliability evaluation has been developed using total values of N-it in the effective channel length region, instead of commonly used substrate current(I-B), impact ionization rate (I-D/I-B), or peak/average N-it values. An accurate degradation model has thus been developed based on the N-it distribution and mobility scattering effect. Moreover, this approach has been successfully used to demonstrate the feasibility for gate-engineering studies.
An automatic method to determine mitral annular lines from 2D+1D precordial echocardiogram
(2000)
Liu, YS
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Ching, YT
;
Chen, SJ
;
資訊工程學系
;
Department of Computer Science
We present a method to determine the sequence of mitral annular lines in 2D + 1D precordial echocardiogram. We first use the optical flow technique a 2-means algorithm to determine a set of possible mitral annular points. A pair of mitral annular points could form the mitral annular line. The problem to determine the sequence of mitral annular lines in 2D + 1D echocardiogram is modeled as a problem to find the shortest path in a graph. The proposed method need very few user inputs. Experimental results show that we can find accurate mitral annular lines.
An improved interface characterization technique for a full-range profiling of oxide damage in ultra-thin gate oxide CMOS devices
(2003)
Chen, SJ
;
Lin, TC
;
Lo, DK
;
Yang, JJ
;
Chung, SS
In this paper, an improved gate-diode technique has been developed for the interface characterization on both n- and p-MOSFET's with gate oxide in the direct tunneling regime. This method has been demonstrated successfully for measuring oxide damage in all of the channel, space-charge (or junction), and drain extension regions in 20Angstrom ultra-thin gate oxide devices. As an application of the present method, the lateral profile of localized oxide damage due to Negative Bias Temperature Instability (NBTI) or Hot Carrier (HC) effect has been demonstrated. It provides us an understanding of the correlation between the device degradation and various stress-induced oxide damage in CMOS devices.
Anisotropic impurity scattering effects on T-c and H-c2 in YBa2Cu3Ox
(1999-03-01)
Lin, JY
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Chen, SJ
;
Chen, SY
;
Chang, CF
;
Yang, HD
We have studied the impurity effects on the superconducting transition temperature T-c and the upper critical field H-c2 in electron irradiated YBa2Cu3Oy with in-plane oxygen defects and YBa2(Cu1-xZnx)(3)O-y. It is found that the effects of the same type of defects or impurities on T-c are the same regardless of the oxygen contents of the samples. Furthermore, T-c decreases slower in irradiated YBa2Cu3Oy than in YBa2(Cu1-xZnx)(3)O-y. This may be well explained by the model that the scattering due to in-plane oxygen defects is more anisotropic than that due to Zn impurities. The different behavior of the reduced slopes (dH(c2)/dT)(Tc)/(dH(c2)/dT)(Tc0) these two types of samples can also be understood in this context. [S0163-1829(99)08309-5].
Charge pumping profiling technique for the evaluation of plasma-charging-enhanced hot-carrier effect in short-N-channel metal-oxide-semiconductor field-effect transistors
(2002-07-01)
Chen, SJ
;
Chung, SSS
;
Lin, HC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Plasma etching of poly-silicon in a metal-oxide-semiconductor field-effect transistor (MOSFET) during the gate definition process induces edge damage at the gate-drain overlap edge. This edge damage will be further enhanced by the antenna effect and cause a more serious hot-carrier (HC) effect, particularly in short-channel devices. We call this phenomenon the plasma-charging-enhanced HC effect. In this paper, this plasma-charging-enhanced HC effect is evaluated by the charge pumping (CP) profiling technique, in which the enhanced damage at the gate-drain overlap gate oxide region can be identified. A three-phase plasma damage mechanism is then proposed to explain the observed effect. According to experimental results, it was shown that the interface traps generated at the gate-drain overlap edge are mainly attributed to the plasma-charging-enhanced HC effect. These interface traps (Nit) become the dominant mechanism of the drain current (ID) degradation, which increases with a reducing channel length (L). Again, the enhanced HC-effect-induced-degradation will dominate the device reliability under long-term operations.
Correlation of supercritical fluid extraction with supercritical fluid chromatography in aqueous matrixes
(1998-05-15)
Yu, T
;
Luo, SK
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Chen, SJ
;
應用化學系
;
Department of Applied Chemistry
A mathematical model is presented for correlating supercritical fluid chromatography (SFC) in aqueous stationary phases with supercritical fluid extraction (SFE) in aqueous matrixes. A solar coaxial countercurrent chromatography apparatus was used for the SFC and SFE experiments. The SFE extraction vessel, i.e., the column for SFC, was mathematically divided into limited layers. During extraction, each layer was considered to undergo a chromatographic process. The plate heights of all the layers were regarded equal throughout the column because pressure drops in the system were negligible. Each layer's chromatographic capacity factor and peak width were calculated using true SFC experimental data, and the sum of all these peak distributions as a function of time gave the extraction efficiency. Accordingly, the SFE analyte recovery curve could be simulated using SFC data and this model. Since SFC operations are more straightforward than SFE operations, SFE optimization may be more easily achieved using this mathematical correlation. The simulated analyte data of large capacity factors matched the experimental results very well. Deviations gradually became greater as analyte capacity factors were decreased. A rationale is proposed that satisfactorily interprets this deviation trend.
Establishing a Web-based DICOM teaching file authoring tool using open-source public software
(2005-09-01)
Lee, WJ
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Yang, CY
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Liu, KL
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Liu, HM
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Ching, YT
Online teaching files are an important source of educational and referential materials in the radiology community. The commonly used Digital Imaging and Communications in Medicine (DICOM) file format of the radiology community is not natively supported by common Web browsers. The ability of the Web server to convert and parse DICOM is important when the DICOM-converting tools are not available. In this paper, we describe our approach to develop a Web-based teaching file authoring tool. Our server is built using Apache Web server running on FreeBSD operating system. The dynamic page content is produced by Hypertext Preprocessor (PHP). Digital Imaging and Communications in Medicine images are converted by ImageMagick into Joint Photographic Experts Group (JPEG) format. Digital Imaging and Communications in Medicine attributes are parsed by dicom3tools and stored in PostgreSQL database. Using free software available from the Internet, we build a Web service that allows radiologists to create their own online teaching file cases with a common Web browser.
Fabrication and metrology of an electro-optic polymer light modulator based on waveguide-coupled surface plasmon resonance
(2005-03-01)
Chyou, JJ
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Chu, CS
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Shih, ZH
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Lin, CY
;
Chen, SJ
This study presents a novel high-efficiency electro-optic (EO). light modulator whose operation is based on the attenuated total reflection effect, which the surface plasmon wave is excited by an incident waveguide light wave. The EO light modulator is fabricated using a nonlinear optical polymer material that is a side-chain EO polyimide with 2-[N-ethyl-4-(tricyanovinyl)anilino]ethanol chromophore. The modulator is characterized, and its performance tested, in terms of the thickness and dielectric constant of the polymer thin film, the EO coefficient, the insertion loss, and the modulation index. Additionally, the dynamic response of the EO light modulator is fully investigated and discussed. (c) 2005 Society of Photo-Optical Instrumentation Engineers.
Finding the mitral annular lines from 2-D+1-D precordial echocardiogram using graph-search technique
(2004-03-01)
Ching, YT
;
Chen, SJ
;
Chang, CL
;
Lin, CY
;
Liu, YH
The apical four-chamber view echocardiogram collected by a transthoracic transducer can be used to evaluate the left ventricle volume. In the diastole, the left ventricle and left atrium become one chamber. In this case, the left ventricle and left atrium need to be separated using a "mitral annular line" so the volume of the left ventricle can be estimated. In this paper, a nearly automatic method for identifying the mitral annular lines from two-dimensional (2-D) + one-dimensional (1-D) precordial four-chamber view echocardiogram is presented. This method employs the optical flow technique and graph-search approach. The mitral annular line sequence is found by finding the shortest path in a weighted directed graph. The vertices in the graph are candidates for the mitral annular lines. The weights on the directed edges are determined using the optical flow technique. The proposed method requires only a physician to provide, a point that is always in the left ventricular chamber. Experimental results show that the average error for the left ventricle volume obtained based on the computed mitral annular lines is 3%.
Magnetic-field dependence of the low-temperature specific heat of La2-xSrxCuO4
(1998-12-01)
Chen, SJ
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Chang, CF
;
Tsay, HL
;
Yang, HD
;
Lin, JY
Recently, possible evidence from the low-temperature specific heat (LTSH) for the lines of nodes in the superconducting order parameter of cuprate superconductors has attracted much attention and is still debated. To clarify this issue and to cover the studies in different carrier doping regimes, we have measured LTSH of La2-xSrxCuO4 (s = 0.10, 0.16, and 0.22) both in zero and applied magnetic fields. In all doping regimes, it is found that the increase in the Linear-T coefficient gamma is proportional to H-1/2, consistent with d-wave supercon ductivity. The data shows clear evidence for an alpha T-2 term at zero magnetic field in LTSH of La1.78Sr0.22CuO4. Furthermore, our results are compared with the recently proposed scaling theory.
Magnetic-field dependence of the low-temperature specific heat of La2-xSrxCuO4
(1998-12-01)
Chen, SJ
;
Chang, CF
;
Tsay, HL
;
Yang, HD
;
Lin, JY
Recently, possible evidence from the low-temperature specific heat (LTSH) for the lines of nodes in the superconducting order parameter of cuprate superconductors has attracted much attention and is still debated. To clarify this issue and to cover the studies in different carrier doping regimes, we have measured LTSH of La2-xSrxCuO4 (s = 0.10, 0.16, and 0.22) both in zero and applied magnetic fields. In all doping regimes, it is found that the increase in the Linear-T coefficient gamma is proportional to H-1/2, consistent with d-wave supercon ductivity. The data shows clear evidence for an alpha T-2 term at zero magnetic field in LTSH of La1.78Sr0.22CuO4. Furthermore, our results are compared with the recently proposed scaling theory.
New degradation mechanisms of width-dependent hot carrier effect in quarter-micron shallow-trench-isolated p-channel metal-oxide-semiconductor field-effect-transistors
(2001-01-01)
Chung, SS
;
Chen, SJ
;
Yang, WJ
;
Yih, CM
;
Yang, JJ
In this study, width-dependent hot-carrier degradation in the p-channel metal-oxide-semiconductor held-effect transistors (p-MOSFETs) with shallow-trench-isolation (STI) is presented. Results show an enhanced drain current degradation with reducing the gate width. A new model and mechanism are proposed to explain the width-dependent hot-carrier (HC) degradation for p-MOSFETs. Based on a two-dimensional channel shortening concept, a new model is developed. The mechanical stress enhanced oxide damage at the STI edge, which will induce channel shortening, is the dominant mechanism for the drain current degradation of the devices after hot-carrier stress. This is a crucial issue for present and future complementary metaloxide semiconductor (CMOS) ultra-large-scale integration (ULSI), and in particular for high-density dynamic random-access memory (DRAM), fabricated using STI technologies.
New experimental evidences of the plasma charging enhanced hot carrier effect and its impact on surface channel CMOS devices
(2001)
Chen, SJ
;
Lin, CC
;
Chung, SS
;
Lin, HC
;
電子工程學系及電子研究所
Plasma etching of poly-silicon gate in CMOS devices induces the plasma edge damage. This damage will be enhanced in the successive plasma processes. New experimental evidences of this effect will be examined in this study. Results have been verified for both surface channel nand p-MOSFETs. First, from the measurements of high-density antenna structures, this enhanced edge damage has been characterized by the charge-pumping (CP) profiling technique. Then, a 4-phase edge damage mechanism has been proposed. For the first time, it was found that a two-peak spatial distribution of the interface state was found near the device drain region. We call it (P) under bar lasma (C) under bar harging (E) under bar nhanced (H) under bar ot (C) under bar arrier (PCE-HC) effect. This enhanced damage effect will induce further device degradation, in particular for the scaled devices.
Reconstruction of 3D geometric models of pulmonary arteries from cardiac CT images
(2002)
Yu, CC
;
Ching, YT
;
Chen, SJ
;
資訊工程學系
;
Department of Computer Science
We present a method to construct the geometric model of the pulmonary arteries from a set of cardiac CT scan images. It is desired that the model is in rectangular meshes. The main difficulties in this work are insufficient resolution along z-direction, the requirement of the rectangular meshes, and the geometric shape of the pulmonary arteries. We present a method that is based on estimation the medial axis and the radii of the vessel along the axis. We evaluate the proposed method using a phantom data set. The proposed method can achieve good reconstructed result for the phantom data set.
Theory of excitonic filling factor v=2 quantum Hall droplet in self-assembled quantum dots
(2005)
Chen, SJ
;
Sheng, WD
;
Hawrylak, P
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電子物理學系
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Department of Electrophysics
We present a theory of excitonic quantum Hall droplet (EXQHD) at filling factor v = 2 in a self-assembled quantum dot subject to a strong perpendicular magnetic field B. Using the method of configuration interaction the ground and excited states, the stability against spin flips, and die optical emission spectrum of v = 2 EXQHD are calculated in both semi-analytical and numerical manner. The v = 2 EXQHD is found to be stable and its characteristic spin related emission pattern is identified.