Browsing by Author "Tseng, TY"

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A method to characterize the dielectric and interfacial properties of metal-insulator-semiconductor structures by microwave measurement
(2002-04-15)
Lue, HT
;
Tseng, TY
;
Huang, GW
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We have developed a method to investigate the dielectric and interfacial properties of gate dielectric thin films by microwave measurement. Ba0.5Sr0.5TiO3 (BST) thin films were deposited on 10 Omega cm (normal) and 10 k Omega cm [high-resistivity, (HR)] silicon substrates at the same time by rf magnetron sputtering. For the BST/HR-silicon, coplanar waveguides (CPW) were fabricated and measured at microwave frequencies with thru-reflect-line calibration while capacitance (C-V) measurements were carried out for BST/normal silicon. From the phase change of CPW transmission line and the maximum capacitance in C-V measurement, the dielectric constants of both the BST thin film and interface layer can be determined. Furthermore, the behaviors of insertion loss versus bias voltage were investigated. The results indicate that our method can provide useful information to study the dielectric and interfacial properties of metal-insulator-semiconductor structures. (C) 2002 American Institute of Physics.
A model of non-homogeneous damped electromagnetic wave and heat equation in ferrite materials
(2002-02-01)
Tung, MJ
;
Chen, R
;
Hsu, CH
;
Tseng, TY
;
電子工程學系及電子研究所
This study uses a closely coupled model to treat the core loss of ferrite by the combination of non-homogeneous damped electromagnetic wave and heat equation. The heat dissipation of ferrites is caused by the core loss, which is a summation of magnetic, dielectric and eddy current losses. Explicit finite difference method solves the coupled equations to calculate core loss and compares it with the measured results. Those results show that this method can be used to analyze electromagnetic and thermal field with temperature dependence of ferrites. (C) 2002 Elsevier Science B.V. All rights reserved.
A novel method to characterize the dielectric and interfacial properties of Ba0.5Sr0.5TiO3 (BST)/Si by microwave measurement
(2002)
Lue, HT
;
Tseng, TY
;
Huang, GW
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We have developed a new method to investigate the dielectric and interfacial properties of gate dielectric thin films by microwave measurement. BST thin films were deposited on 10 Omega-cm (normal) and 10 kOmega-cm (high-resistivity, HR) silicon substrates. at the same time by RF magnetron sputtering. For the BST/HR-silicon, coplanar waveguides (CPW) were fabricated and measured at microwave frequencies with Thru-Reflect-Line (TRL) calibration while CV measurements were carried out for BST/normal-silicon. From the phase change of CPW transmission line and the maximum capacitance in CV measurement, the dielectric constants of both the BST thin film and interface layer can be determined. Furthermore, the behaviors of insertion loss versus bias voltage were found to be correlated with the trap states density. The results indicate that our method can provide useful information to study the dielectric and interfacial properties of metal - insulator - semiconductor (MIS) structures.
A-axis YBCO thin films deposited by DC magnetron sputtering
(1997-01-01)
Tsai, WC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A-axis YBCO thin films deposited on SrTiO3 and MgO substrates were prepared using the template-layer method by off-axis magnetron sputtering. The thin films deposited on MgO with template layers displayed better electrical properties and crystallinity than those deposited on the substrates without template layers, whereas the crystallinity of films deposited on SrTiO3 by the template-layer method showed no improvement. The surface morphology of the films, observed by high-resolution scanning electron microscopy, indicates that the homoepitaxial growth of the a-axis films on template layers on MgO and SrTiO3 results in rougher surfaces than in the case of heteroepitaxial growth of template layers. The possible mechanisms contributing to these differences in surface roughness were carefully investigated. Atomic force microscopy was also used to characterize the initial growth of a-axis films on MgO and SrTiO3. According to the results, the initial growth of a-axis films on MgO and SrTiO3 resembles that of island growth.
AC permeability of the flux-line liquid in the anisotropic high-T-c superconducting crystals
(1996-09-01)
Wu, CJ
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
AC properties of the flux-line liquid in the anisotropic high-temperature superconducting crystals in a parallel field are theoretically investigated. The ac responses in the simple flux-flow regime are analyzed from associated effective ac-magnetic permeability calculated on the hydrodynamic theory basis. The responses are studied as functions of anisotropic ratio and sample dimensions. The results illustrate the influence of the platelet crystal's size on permeability in the anisotropic superconductors while in the isotropic superconductors, the relationship of responses between a square rod and cylinder is found. It indicates that the permeability of a cylinder can be essentially replaced by that of a square rod and vice versa. The geometric effect on response is also elucidated in the isotropic superconductors.
AC permeability of the flux-line liquid in the anisotropic high-T-c superconducting crystals
(1996-09-01)
Wu, CJ
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
AC properties of the flux-line liquid in the anisotropic high-temperature superconducting crystals in a parallel field are theoretically investigated. The ac responses in the simple flux-flow regime are analyzed from associated effective ac-magnetic permeability calculated on the hydrodynamic theory basis. The responses are studied as functions of anisotropic ratio and sample dimensions. The results illustrate the influence of the platelet crystal's size on permeability in the anisotropic superconductors while in the isotropic superconductors, the relationship of responses between a square rod and cylinder is found. It indicates that the permeability of a cylinder can be essentially replaced by that of a square rod and vice versa. The geometric effect on response is also elucidated in the isotropic superconductors.
AC response of the vortex liquid in the high-T-c superconducting cylinder
(1996-04-01)
Wu, CJ
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Tseng, TY
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The ac response of the vortex liquid of a high-T-c superconducting cylinder in the parallel field configuration is examined theoretically The ac properties are analyzed from the associated complex ac permeability calculated on the basis of hydrodynamics theory. The permeability is primarily dominated by two frequency-dependent penetration lengths which are also shown to be independent of the geometries considered. in the simple flux-flow regime, the second peak in ac loss is observed to be enhanced while the first peak is depressed for the superconducting cylinder In the viscous flux liquid, the ac response is found to rely on the viscosity, ratio of shear modulus to nonlocal compressional modulus, and the geometries discussed. The results indicate some basic difference in ac permeabilities between superconducting cylinder and slab.
An improved two-frequency method of capacitance measurement for SrTiO3 as high-k gate dielectric
(2002-09-01)
Lue, HT
;
Liu, CY
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
An improved two-frequency method of capacitance measurement for the high-k gate dielectrics is proposed. The equivalent circuit model of the MOS capacitor including the four parameters of intrinsic capacitance, loss tangent, parasitic series inductance, and series resistance is developed. These parameters can be extracted by independently measuring the capacitor at two different frequencies. This technique is demonstrated for high-k SrTiO3 gate dielectrics and the results show that the calibrated capacitances are invariant over a wide range of frequency. In addition, the extracted loss tangent, inductance and resistance are independent on gate voltage and frequency. The effect of series resistance on the frequency dispersion of the capacitance can be also explained by this model. These results indicate that this modified technique can be incorporated in the routine capacitance-voltage (C-V) measurement procedure providing the physically meaningful data for the high-k gate dielectrics.
Analysis of AC electrical response for radio-frequency sputtered (Ba0.5Sr0.5)TiO3 thin film
(1999-06-01)
Wang, YP
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Through the measurement of dielectric dispersion as a function of frequency (100 Hz less than or equal to f less than or equal to 1 MHz), we investigated the trapping dielectric relaxation of r.f.-sputtered (Ba0.5Sr0.5)TiO3 film and proposed an equivalent circuit on the basis of the admittance and capacitance spectra. Admittance spectral studies in the temperature range of 200-420 K revealed the existence of a trap level. The trap, located at 0.05 eV, is envisaged to be responsible for the origin of dielectric relaxation and carrier concentration. The equivalent circuit, consisting of a series trapping resistance and capacitance combination in parallel with leakage resistance and high frequency limit capacitance, is adopted to explain satisfactorily the AC response and to identify the contribution of the shallow trap on the electrical properties of BST thin film. (C) 1999 Elsevier Science S.A. All rights reserved.
Application of on-wafer TRL calibration on the measurement of microwave properties of Ba0.5Sr0.5TiO3 thin films
(2001-11-01)
Lue, HT
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A series of Al/Ba0.5Sr0.5TiO3 (BST)/sapphire multi-layered coplanar waveguide (CPW) transmission lines of different geometries and thin-film configurations was fabricated. We employed an accurate on-wafer Through-Line-Reflect (TRL) calibration technique and quasi-TEM analysis to measure the dielectric constant, loss tangent, and tunability of BST thin films using this CPW structure. Experimental results show that the overall insertion loss is less than 3 dB/cm even at frequencies as high as 20 GHz, which is the lowest obtained to date for metal/BST CPW devices. This result indicates that, with optimized impedance matching, normal conductors are also possibly suitable for fabricating low-loss tunable phase-shifter devices.
Ba(Ti0.8Sn0.2)O-3 thin films prepared by radio-frequency magnetron sputtering for dynamic random access memory applications
(1999-05-01)
Kuo, YF
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Tseng, TY
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Polycrystalline thin films of Ba(Ti0.8Sn0.2)O-3 100 nm thick were deposited on Pt/TiO2/SiO2/Si(100) substrates by radio-frequency magnetron sputtering at various substrate temperatures. The films crystallized with high (111) diffraction intensity at a substrate temperature of 650 degrees C, had good crystalline quality, and exhibited a large dielectric constant. The dielectric constant and leakage current of the films increased with an increase of the intensity ratio of (111)/(110) peaks. This study also established a correlation between the dielectric constant, leakage current, and crystallinity of the films. (C) 1999 The Electrochemical Society. S1099-0062(98)11-098-2. All rights reserved.
(Ba,Sr)TiO3 thin films: Preparation, properties and reliability
(1999)
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
(Ba,Sr)TiO3 thin films are important capacitor materials for future gigabit era dynamic random access memory (DRAM) applications. This article reviews the technological aspects of BST films, including thin films deposition techniques, post annealing, physical, electrical and dielectric characteristics of the films, effects of bottom electrode materials, complex plane analysis of AC electrical, dielectric relaxation, and defect and reliability phenomena associated with the films. In addition, possible future developments are briefly summarized.
Bistable resistive switching of a sputter-deposited Cr-doped SrZrO3 memory film
(2005-06-01)
Liu, CY
;
Wu, PH
;
Wang, A
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Jang, WY
;
Young, JC
Sputter-deposited Cr-doped SrZrO3-based metal-insulator-metal structures exhibited bistable resistive reversible switching as observed under bias voltage and voltage pulse. The ratio of resistance of the two leakage states (high-H, low-L) was about five orders of magnitude. The conduction of the L-state satisfied Frenkel-Poole emission and that of the H-state followed ohmic mechanism, causing the resistance ratio to decrease with increasing bias voltage. The transition time of H- to L-state was five orders of magnitude higher than that of L- to H-state. The transition from H- to L-state was the restricted part for reversible switching operation. The difference in transition time of the two states should be related to the respective conduction mechanisms.
Characteristics and electrochemical performance of supercapacitors with manganese oxide-carbon nanotube nanocomposite electrodes
(2005)
Lee, CY
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Tsai, HM
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Chuang, HJ
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Li, SY
;
Lin, P
Supercapacitor characteristics of manganese oxide/nickel (MnOx/Ni) and manganese oxide/carbon nanotubes/nickel (MnOx/CNTs/Ni) nanocomposite electrodes were investigated in this study. The CNTs were deposited on the Ni substrate by electrophoresis in a 0.5 mg CNT/1 mL dimethylformamide solution, whereas the MnOx were synthesized by anodic deposition in a 0.16 M manganese sulfate pentahydrate aqueous solution on substrates. The crystallinity and surface morphology of these electrodes were determined by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The capacitive properties of these electrodes were demonstrated by cyclic voltammetry with scan rates ranging from 5 to 100 mV/s. The specific capacitances of the MnOx/CNT/Ni nanocomposite electrode were 415 and 388 F/g with scan rates of 5 and 100 mV/s, respectively. After 1000 cycles of operation, this electrode can maintain 79% of its original capacitance. These MnOx/CNT/Ni nanocomposite electrodes possessing good electrochemical reversibility and high capacitance may be appropriate for supercapacitor application in the future. (c) 2005 The Electrochemical Society.
Characterization of porous silicate for ultra-low k dielectric application
(2002-07-01)
Liu, PT
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Chang, TC
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Hsu, KC
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Tseng, TY
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Chen, LM
Thermal stability of a porous low-k film is a critical issue for application consideration in the back-end-of-line. In this study, thermal stability of the porous silicate has been investigated by changing the thermal processing temperatures. Experimental results have shown that the dielectric constant of the porous silicate still remains below 2.0 after thermal processing at 500 degreesC for I h. A series of material analysis techniques and electrical characteristics have been used to verify the physical and chemical characteristics of the porous silicate film. (C) 2002 Elsevier Science B.V. All rights reserved.
Characterization of yttria-stabilized zirconia thin films grown by planar magnetron sputtering
(1997-08-28)
Tsai, WC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Yttria-stabilized zirconia (YSZ) thin films were grown on Si by rf magnetron sputtering. Sputtering gun was positioned at various angles to the substrate normal to change the amount of plasma bombardment on the as-deposited films. YSZ films grown by off-axis sputtering (90 degrees) are readily (200)-preferred orientated but the preferred orientation of the film is deteriorated when the growth angle is decreased and, consequently, plasma bombardment is increased due to the decreasing growth angles. The off-axis grown YSZ films exhibit atomically smooth interfaces, which are not observed for those films grown by on-axis sputtering. The variation of oxide charge with the growth angle is studied with the Al/YSZ/Si structure. The plasma bombardment plays an important role on the crystallinity and, therefore, the defect type of the films and is also considered to be responsible for the Si outdiffusion occurring in an on-axis grown film. (C) 1997 Elsevier Science S.A.
CMP of low-k methylsilsesquiazane with oxygen plasma treatment for multilevel interconnect applications
(2004)
Chang, TC
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Tsai, TM
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Liu, PT
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Chen, CW
;
Yan, ST
The effect of oxygen plasma treatment on methylsilsesquiazane (MSZ) dielectric was investigated for chemical mechanical planarization (CMP) process. Oxygen plasma treatment was implemented before CMP. Experimental results have shown that the polishing rate of MSZ film with O-2 plasma pretreatment is increased as much as two order of magnitude more than that of MSZ without O-2 plasma pretreatment. Moreover, the electrical properties of post-CMP MSZ are close to those of an as-cured MSZ. These results indicate that the modified surfaces resulting from O-2 plasma treatment increase the polishing rate of MSZ. After polishing, the MSZ film still maintains a low-k quality. (C) 2004 The Electrochemical Society.
Conduction mechanism and temperature-dependent current-voltage in (Ba, Sr)TiO3 thin films
(1998-08-01)
Tsai, MS
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
RF magnetron sputtered (Ba, Sr)TiO3 (BST) thin films were deposited on Pt/SiO substrate with various O-2/(O-2 + Ar) mixing ratios (OMR) ranging from 0 to 60%. Two possible conduction mechanisms of the BST thin films, the Poole-Frenkel (PF) transport (bulk limited conduction) and the Schottky emission (SE) (electrode limited conduction) were studied. Experimental results indicated that the BST films prepared at low OMR (0-25%) exhibit the SE mechanism dominated below the transition electric field of 490 kV/cm and the PF transport mechanism dominated beyond 490 kV/cm; and while those prepared at high OMR (40-60%) display the SE mechanism dominated both below and beyond the transition electric field. The difference in dominant mechanism (bulk and electrode limited conduction) between films was ascribed to concentration variation of the oxygen vacancy in the films.
Conduction mechanisms in amorphous and crystalline Ta2O5 thin films
(1998-05-01)
Ezhilvalavan, S
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Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Electrical properties and leakage current mechanisms of amorphous and polycrystalline tantalum pentoxide (Ta2O5) films were studied. Ta2O5 thin films were deposited on Pt/SiO2/n-Si substrate by reactive magnetron sputtering and then annealed at temperatures ranging from 500 to 800 degrees C for 30 min in O-2. The as-deposited films were amorphous and showed good electrical properties in terms of a dielectric constant of about 31 and leakage current density of 10(-10) A/cm(2) at 100 kV/cm. The leakage current flowing through Ta2O5 film increases from 10(-10) to 10(-7) A/cm(2) following the annealing. The conduction mechanism at low electric fields (100 kV/cm) is due to Ohmic conduction. On the other hand Schottky mechanism dominates at the intermediate fields (100-350 kV/cm) and Poole-Frenkel becomes predominant at high fields (>350 kV/cm). The increase in leakage current density in the crystallized film is due to Si penetrated into the Ta2O5 grain and grain boundary from the underlying SiO2/n-Si substrate. (C) 1998 American Institute of Physics.
Copper-catalyzed ZnO nanowires on silicon (100) grown by vapor-liquid-solid process
(2003-01-01)
Li, SY
;
Lee, CY
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Tseng, TY
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The ZnO nanowires were synthesized using vapor liquid-solid (VLS) growth process on copper coated p-type Si (100) Substrate. Copper catalyzed the growth of ZnO nanowires of diameters 80-150 nm and lengths of 2.5-4.0 mum. The ZnO nanowires had hexagonal structure and exhibited <0002> orientation. The photoluminescence measurements showed that the ZnO nanowires had a strong ultraviolet emission at around 381 nm and a very weak green emission around 520 nm. (C) 2002 Elsevier Science B.V. All rights reserved.