Browsing by Author "Chiou, BS"

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A floating well method for exact capacitance-voltage measurement of nano technology
(2003-06-01)
Su, HD
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Chiou, BS
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Wu, SY
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Chang, MH
;
Lee, KH
Small gate area with short gate length reduces the C-V distortion of ultrathin oxide devices, but results in high parasitic capacitance/total capacitance ratio. The floating well method can exclude the parasitic capacitance to obtain accurate inversion oxide thickness without using any dummy pattern. It is suitable for nano technology.
Analysis of average transport critical current density of oxide superconductors deposited on a silver base
(1996-01-01)
Lee, WD
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Yang, TJ
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Chiou, BS
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電子物理學系
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電控工程研究所
Considering the resistivity of a silver base and the contact resistance of a silver base with a bulk superconductor, the dependence of average critical current density J(c)(D,H-a) of a high-T-c, oxide superconductor deposited oil a silver base on the sample dimension D and the applied magnetic field H-a is calculated using a generalized critical-state model, which was recently extended to low field by Chen and Yang [Physica C 224 (1994) 345]. The self-field effect of the average critical current was also taken into account in the model. Based on the generalized critical state model, new behaviors of J(c)(D, H-a) in the low-field range of H-c1 less than or equal to H-a much less than H-c2 are obtained. In addition, a constant J(c)(D, H-a) for 0 less than or equal to H-a less than or equal to H-c1 is obtained, which is different from the results derived from a model that does not include the self-field effect. However, these theoretical results can be fitted to the experimental data to obtain some important macroscopic material parameters and may be used to interpret the dimension effect of transport J(c) of a high-T-c oxide superconductor deposited on a silver base.
Analysis of the dielectric characteristics for polycrystalline Ba(0.65)Sr(0.35)TiO(3) (I)-frequency dependence in the paraelectric state
(2000-11-01)
Liou, JW
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Chiou, BS
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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
The frequency and d.c. field dependences of dielectric properties of Ba(0.65)Sr(0.35)TiO(3) (BST) with various grain sizes (0.87 mum to 5.43 mum) have been studied in the paraelectric state. The frequency response is analyzed by two approximated power laws obtained on the basis of the Cole-Cole expression. The distribution of relaxation times in BST is broader for specimens with finer grains. The d.c. field is found to affect the static permittivity epsilon (0) rather than the distribution of relaxation times. The effect of the d.c. field on the dielectric permittivity is suppressed for samples with smaller grains and transition broadening is presumed to cause this suppression. It is concluded that both the temperature dependence and the frequency response of the dielectric characteristics of Ba(0.65)Sr(0.35)TiO(3) are suppressed by the transition broadening. (C) 2000 Kluwer Academic Publishers.
Analysis of the dielectric characteristics for polycrystalline Ba0.65Sr0.35TiO3 (I)-frequency dependence in the paraelectric state
(2000-11-01)
Liou, JW
;
Chiou, BS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The frequency and d.c. field dependences of dielectric properties of Ba0.65Sr0.35TiO3 (BST) with various grain sizes (0.87 mum to 5.43 mum) have been studied in the paraelectric state. The frequency response is analyzed by two approximated power laws obtained on the basis of the Cole-Cole expression. The distribution of relaxation times in BST is broader for specimens with finer grains. The d.c. field is found to affect the static permittivity epsilon (0) rather than the distribution of relaxation times. The effect of the d.c. field on the dielectric permittivity is suppressed for samples with smaller grains and transition broadening is presumed to cause this suppression. It is concluded that both the temperature dependence and the frequency response of the dielectric characteristics of Ba0.65Sr0.35TiO3 are suppressed by the transition broadening. (C) 2000 Kluwer Academic Publishers.
Analysis of the dielectric characteristics for polycrystalline Ba0.65Sr0.35TiO3 (II) - d.c. field dependence with a modified bias equation
(2000-11-01)
Liou, JW
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Chiou, BS
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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
The effect of direct-current (d.c.) biasing on the dielectric properties of Ba0.65Sr0.35TiO3 (BST) with various grain sizes (0.87 mum to 5.43 mum) have been studied in the paraelectric state. The leakage current of BST samples is proportional to the biasing field. Specimens with larger grains exhibit higher leakage current under biasing. The bias equation used in the literature to predict the d.c. field dependence of permittivity is modified by introducing a bias exponent parameter beta. This modified bias equation gives a better fit to the experimental results both in this study and in the literature. Similar trends of alpha (representing the distribution of relaxation times), beta, and the variance of lattice distortion with grain sizes suggests that beta is a material parameter. It is concluded that the temperature dependence, the frequency response and d.c. field effect for the dielectric characteristics of Ba0.65Sr0.35TiO3 are all suppressed by the transition broadening. (C) 2000 Kluwer Academic Publishers.
Antireflective coating for ITO films deposited on glass substrate
(1999-09-01)
Chiou, BS
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Tsai, JH
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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
The refractive index n of radio-frequency (r.f.) magnetron sputtered indium tin oxide (ITO) films varies with sputtering parameters, such as sputtering power and oxygen percentage in the sputtering ambient. In this study, the feasibility to fabricate multilayer antireflective (AR) coating with a single ITO target by controlling the sputtering conditions is explored. Reduction in the reflectance can be achieved by using a one-quarter-wavelength inner layer ITO with a refractive index n = 1.87 and a one-quarter-wavelength outer layer ITO with n = 2.17. Hence, a single ITO target suffices in the preparation of multilayer AR coating. This simplifies the deposition processes and equipment for the fabrication of AR coating. Surface corrugation, another approach to the reduction of reflectance, is also discussed.
Barrier layer effect of tantalum on the electromigration in sputtered copper films on hydrogen silsesguioxane and Si0(2)
(2002-05-01)
Sung, WL
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Chiou, BS
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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
As IC devices scale down to the submicron level, the resistance-capacitance (RC) time delays are the limitation to circuit speed. A solution is to use low dielectric constant materials and low resistivity materials. In this work, the influence of underlying barrier Ta on the electromigration (EM) of Cu on hydrogen silsesquioxane (HSQ) and SiO2 substrates was investigated. The presence of a Ta barrier not only improves the adhesion between Cu and dielectrics, but also enhances the crystallinity of Cu film and improves the Cu electromigration resistance. The activation energy obtained suggests a grain boundary migration mechanism and the current exponent calculated indicates the Joule heating effect.
Barrier layer effect of titanium-tungsten on the electromigration in sputtered copper films on polyimide
(2000-02-01)
Wang, HW
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Chiou, BS
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電子物理學系
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電子工程學系及電子研究所
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Department of Electrophysics
Titanium-tungsten is employed as the diffusion barrier in a Cu/barrier/polyimide/Si system. The electromigration damage (EMD) of Cu with a TiW barrier is investigated utilizing an empirical formula. Two activation energies are obtained suggesting a surface electromigration mechanism at low temperature (140-190 degrees C) and a combined migration mechanism at high temperature (190-230 degrees C). The presence of the TiW barrier layer improves the high temperature electromigration resistance. The effects of the TiW barrier on the microstructure and electrical properties of Cu metallization are discussed.
Bi-mode breakdown test methodology of ultrathin oxide
(2003-12-01)
Su, HD
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Chiou, BS
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Ko, CY
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Wu, SY
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Chang, MH
The breakdown detections of ultrathin oxide (1.4-2 nm) using a fast voltage ramp have been studied. It was found that the breakdown voltage test of deep sub-micron technology requires the reduction of the gate area of test patterns and therefore the increase of the number of structures due to a large inversion gate current at a low electrical field (> 0. 1 A/cm(2) at 1 V) caused by the scaling down of oxide thickness. The gate current in accumulation mode is smaller than that in inversion mode by more than two orders of magnitude at a low applied voltage (1 V). The bi-mode model proposed in this paper applies a voltage stress in the inversion mode and detects failure in the accumulation mode to enhance the robustness of the breakdown test and reduce the possibility of pseudo breakdown failure. With the proposed method, a shorter test time with an increased test pattern area to improve the efficiency of the breakdown test of ultrathin oxide is achieved.
Characteristics of low-temperature-prepared (Ba, Sr)TiO3 films post treated by novel excimer laser annealing
(2002)
Shye, DC
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Chiou, BS
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Hwang, CC
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Chen, JS
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Su, IW
Thin (Ba0.5Sr0.5)TiO3 (BST) films were sputtered on Pt[FiN/Ti/Si multilayer substrates at very low temperature (150degrees C). A novel process, using wavelength 248-nm KrF excimer laser annealing (ELA), has been undertaken to implement barium strontium titanate (BST) films at a low process temperature of 300degrees C. The crystallinity and dielectric constant are greatly improved after ELA treatment. In this work, the variation of texture was investigated. Besides, the escaped oxygen atoms from BST films were detected in-situ using a residual gas analyzer (RGA) during ELA process. Thus, the degradation of upper surface is strongly influenced by the laser energy fluence for an ELA-BST film.
Characteristics of oxide breakdown and related impact on device of ultrathin (2.2 nm) silicon dioxide
(2003-09-01)
Su, HD
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Chiou, BS
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Wu, SY
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Chang, MH
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Lee, KH
The oxide breakdown characteristics of ultrathin oxide (2.2 nm) have been studied in this paper. Light emission microscopy (EMMI) analysis shows that each breakdown has a specific failure location with a random distribution. Gate leakage current increases for all soft breakdown events are similar. After soft breakdown, the I-V curve still shows the representative direct tunneling characteristics and can be fitted using a dual direct tunneling (DDT) model. Soft breakdown has no effect on the drain current of long-channel devices. Breakdown at the polyedge appears to be of the hard-breakdown mode and results in an abrupt increase in gate current. For short-channel devices, the polyedge is always within the damaged region of an oxide because the channel is shorter than the damaged region of the oxide. Hence, only hard breakdown resulting in permanent damage is observed in short-channel devices.
Characterization and conductive coating of phosphors for improved brightness
(2005-04-30)
Chang, CH
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Chiou, BS
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Chen, KS
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Ho, JC
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電子工程學系及電子研究所
In this study, the phosphors used in CRTs are coated with In2O3 conductive layer derived from the hydrolysis of indium chloride. The conductive coating retards/eliminates charging-up on the phosphor surface during the bombardment of the electrons and improves the cathodoluminescent brightness of the phosphor. However, the non-emissive conductive coating also degrades the cathodoluminescent brightness when it is too thick. The cathodoluminescent brightness increases initially with the amount of coating, reaches a maximum at 10 wt.% InCl3, and decreases with further increase of coating. It is found that with a 10 wt.% InCl3 coating, the brightness of phosphor increases by 20% at 500 V and 1 mu A. (c) 2004 Published by Elsevier B.V.
Curing of polyimide and the effect of the TEOS SiO2 barrier layer on the electromigration of sputtered Cu with polyimide passivation
(2002-01-01)
Hung, HY
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Chiou, BS
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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
The curing process of polyimide and the electromigration of copper films with polyimide (PI) passivation are studied. Thermal analysis of polyimide suggests that imidization completes at similar to200degreesC with an endothermic reaction associated with the breaking of the C-OH and N-H bonds as revealed by Fourier transformation infrared spectroscopy (FTIR). Although there is 89.8% weight loss when PI is heated from 20 degreesC to 200 degreesC, outgassing of PI passivation is still observed at higher temperatures. Carbon, nitrogen, and oxygen atoms diffuse into Cu during thermal processing of PI/Cu films. The tetraethyl orthosilicate (TEOS) SiO2 films are used as the barrier layer between PI and Cu to retard the poisoning of Cu. The effect of TEOS SiO2 film on electromigration of Cu is investigated.
Current-temperature characteristics of low-temperature-sputtered (Ba,Sr)TiO3 films post treated by rapid thermal annealing
(2002)
Shye, DC
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Chen, JS
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Kuo, MW
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Chou, BCS
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Jan, CK
This work reports the current-temperature characteristics of the low-temperature-sputtered (Ba0.8Sr0.2)TiO3 (BST) film post treated by rapid thermal annealing (RTA) in O-2 ambient. The top electrode was biased under negative/positive voltage to investigate the interface properties of the Pt/BST/Pt multifilm. As the results, the current density of the RTA-treated BST film was greatly reduced owing to compensation of oxygen vacancies. The RTA-treated BST thin film biased at negative voltage exhibits a negative temperature-coefficient-resistivity (NTCR) behavior, but, intriguingly, that biased at positive voltage reveals a positive temperature-coefficient-resistivity (PTCR) behavior. According to the leakage current analysis, the Schottky emission dominates the negative biased current at upper interface, but the Heywang barrier scattering confines the positive biased current.
DC field dependence of the dielectric characteristics of doped Ba0.65Sr0.35TiO3 with various grain sizes in the paraelectric state
(1997-07-01)
Liou, JW
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Chiou, BS
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Different grain sizes of ferroelectric Ba0.65Sr0.35TiO3 doped with 1.0mol% MgO and 0.05mol% MnO2 were prepared to investigate the DC field dependence of dielectric characteristics. A transition broadening is observed as grain size decreases. The broadening is attributed to the variance of lattice distortion in the materials. As the grain size increases, both the maximum dielectric constant k(max) at T-c and the dielectric tunability (percentage change of dielectric constant under a DC field) increase. A phenomenological equation can be fit to the DC field dependence of the dielectric constant. The phenomenological coefficient obtained is strongly dependent on the grain size and the temperature. Above the phase transition; a ''behavior-transformation'' temperature T-b is observed. At temperatures below T-b, the dielectric loss factor that is dominated by intrinsic loss is reduced when the DC field is applied. While at temperatures above T-b; the loss factor is dominated by the conduction loss and is raised by the DC field.
DC field dependence of the dielectric characteristics of doped Ba0.65Sr0.35TiO3 with various grain sizes in the paraelectric state
(1997-07-01)
Liou, JW
;
Chiou, BS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Different grain sizes of ferroelectric Ba0.65Sr0.35TiO3 doped with 1.0mol% MgO and 0.05mol% MnO2 were prepared to investigate the DC field dependence of dielectric characteristics. A transition broadening is observed as grain size decreases. The broadening is attributed to the variance of lattice distortion in the materials. As the grain size increases, both the maximum dielectric constant k(max) at T-c and the dielectric tunability (percentage change of dielectric constant under a DC field) increase. A phenomenological equation can be fit to the DC field dependence of the dielectric constant. The phenomenological coefficient obtained is strongly dependent on the grain size and the temperature. Above the phase transition; a ''behavior-transformation'' temperature T-b is observed. At temperatures below T-b, the dielectric loss factor that is dominated by intrinsic loss is reduced when the DC field is applied. While at temperatures above T-b; the loss factor is dominated by the conduction loss and is raised by the DC field.
Dependence of polarization on temperature coefficient resistance of (Ba, Sr)TiO3 thin films post-treated by RTA
(2003-04-01)
Shye, DC
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Chiou, BS
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Kuo, MW
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Chen, JS
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Chou, BCS
The temperature coefficient of resistance (TCR) characteristics of Pt/(Ba0.8Sr0.2)TiO3 (BST)/Pt thin-film resistors are studied for the BST films with rapid thermal annealing (RTA) treatments. The polarizations induced by bias voltages greatly influence the TCR characteristics. The RTA-treated BST thin film exhibits negative TCR (NTCR) behavior at a negative voltage, but, intriguingly, positive TCR (PTCR) behavior at a positive voltage. According to the leakage current analysis, Schottky emission dominates the negatively biased current at the upper interface, but Heywang barrier scattering confines the positive biased current. (C) 2003 The Electrochemical Society.
Deposition of indium tin oxide films on polycarbonate substrates by radio-frequency magnetron sputtering
(1997-04-20)
Wu, WF
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Chiou, BS
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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
Indium tin oxide (ITO) films have been deposited onto polycarbonate (PC) substrates by radio frequency (rf) magnetron sputtering. The influence of the oxygen content during sputtering on the film morphology, and the electrical and optical properties of the films have been investigated. Both the refractive index and the extinction coefficient decrease with increasing oxygen content. In this study, the figures of merit T-10/R-sh of the films are higher than those for low-temperature sputtered films reported in the literature. (C) 1997 Elsevier Science S.A.
Deposition of indium tin oxide films on polycarbonate substrates by radio-frequency magnetron sputtering
(1997-04-20)
Wu, WF
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Chiou, BS
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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
Indium tin oxide (ITO) films have been deposited onto polycarbonate (PC) substrates by radio frequency (rf) magnetron sputtering. The influence of the oxygen content during sputtering on the film morphology, and the electrical and optical properties of the films have been investigated. Both the refractive index and the extinction coefficient decrease with increasing oxygen content. In this study, the figures of merit T-10/R-sh of the films are higher than those for low-temperature sputtered films reported in the literature. (C) 1997 Elsevier Science S.A.
Dielectric characteristics of doped Ba1-xSrxTiO3 at the paraelectric state
(1997-10-30)
Liou, JW
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Chiou, BS
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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
Ba1-xSrxTiO3 (x=0 to 1) ferroelectric ceramics doped with 1.0 mol.% MgO and 0.05 mol.% MnO2 were prepared with a rate-controlled sintering profile. The lattice constant of this BST system decreases as the strontium molar fraction increases. This is due to the smaller Sr2+ ionic radius than that of Ba2+. The temperature dependence of the dielectric constant is measured at 10 kHz. A linear relation of the Curie temperature of the BST system to the Sr fraction for x less than or equal to 0.75 is observed. When this reaction is fitted to a modified Curie-Weiss law, two parameters, the critical exponent and the diffuseness parameter, which represent the order of transition broadening, can be calculated. From the values of these two parameters, it is suggested that the physical meanings of these two parameters are correlated to each other. The transition broadening is greatest for x = 0.5 owing to the most composition fluctuation. Dipole relaxation of the composition with x = 0.25 is observed at frequencies above 1 MHz. On the basis of Cole-Cole analysis, a low frequency relaxation due to dopants Mn4+ at below 50 kHz is observed. (C) 1997 Elsevier Science S.A.