Browsing by Author "Lue, HT"

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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 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.
Addenda to photoluminescence and electron paramagnetic resonance studies of defect centers in porous silicon
(2002-01-15)
Lue, HT
;
Tseng, CY
;
Lue, JT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This work includes addenda to the paper entitled photoluminescence and electron paramagnetic resonance studies of defect centers in porous silicon (PS) which was published in this journal. The readers can readily obtain the principal values of g(parallel to) and g(perpendicular to) from the de-convolution of the effective principal g-values of the spin resonance data measured at various rotating angles of the magnetic field and the crystal axes. (C) 2002 Elsevier Science B.V. All rights reserved.
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.
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.
Device modeling of ferroelectric memory field-effect transistor (FeMFET)
(2002-10-01)
Lue, HT
;
Wu, CJ
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A numerical analysis of the electrical characteristics for the ferroelectric memory field-effect transistors (FeMFETs) is presented. Two important structures such as the metal-ferroelectric-insulator-semiconductor field-effect transistor (MFISFET) and metal-ferroelectric-metal-insulator-semiconductor field-effect transistor (MFMISFET) are considered. A new analytic expression for the relation of polarization versus electric field (P-E) is proposed to describe the nonsaturated hysteresis loop of the ferroelectric material. In order to provide a more accurate simulation, we incorporate the combined effects of the nonsaturated polarization of ferroelectric layers and the nonuniform distributions of electric field and charge along the channel. We also discuss the possible nonideal effects due to the fixed charges, charge injection, and short channel. The present theoretical work provides some new design rules for improving the performance of FeMFETs.
Device Modeling of ferroelectric memory field-effect transistor for the application of ferroelectric random access memory
(2003-01-01)
Lue, HT
;
Wu, CJ
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
An improved theoretical analysis on the electrical characteristics of ferroelectric memory field-effect transistor (FeMFET) is given. First, we propose a new analytical expression for the polarization versus electric field (P-E) for the ferroelectric material. It is determined by one parameter and explicitly includes both the saturated and nonsaturated hysteresis loops. Using this expression, we then examine the operational properties for two practical devices such as the metal-ferroelectric-insulator-semiconductor field-effect transistor (MFIS-FET) and metal-ferroelectric-metal-insulator-semiconductor field-effect transistor (MFMIS-FET) as well. A double integral also has been used, in order to include the possible effects due to the nonuniform field and charge distribution along the channel of the device, to calculate the drain current of FeMFET. By using the relevant material parameters close to the (Bi, La)(4)Ti3O12 (BLT) system, accurate analyses on the capacitors and FeMFET's at various applied biases are made. We also address the issues of depolarization field and retention time about such a device.
Effects of nitridation of silicon and repeated spike heating on the electrical properties of SrTiO3 gate dielectrics
(2002-12-02)
Liu, CY
;
Lue, HT
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Electrical properties of SrTiO3 (STO) gate dielectrics on Si substrates grown by rf-magnetron sputtering were studied. We employed the surface nitridation and repeated spike heating to improve the interfacial properties of STO/Si. The nitrogen was moderately incorporated at the interface by first growing a thin SiON layer and then removing this sacrificial layer before growing STO gate dielectric. The experimental results indicate that this nitridation treatment may retard the formation of thin interfacial layer during the high-temperature growth of STO gate dielectric and consequently decrease the equivalent oxide thickness (EOT) by about 10% toward 24% at various deposition pressures. The STO gate dielectric with this nitridation treatment exhibited slightly lower leakage current at an accumulation region and nearly 2 orders of magnitude lower leakage current at an inversion region. The repeated spike heating technique was also employed to deposit a STO gate dielectric at repeated oscillating temperatures. The results show that this thermal treatment reduced the interfacial trap states and the leakage current was also reduced by about 1 order of magnitude at the same EOT. (C) 2002 American Institute of Physics.
Fermi and anti-Fermi glass transition and subband resonant quantum tunneling in Nb/Ti metallic multilayer films
(2000-04-01)
Lue, JT
;
Liang, SY
;
Lee, YW
;
Lue, HT
;
電子工程學系及電子研究所
Multilayer of Nb/Ti and NbN/Ti films with 30 periodic structure were sputtered onto silicon substrates. The current-voltage characteristics measured along the vertical junction at low temperatures exhibit nonlinear step-wise curves. The resonant subband quantum tunneling in the metallic multiple quantum wells can satisfactorily express these peculiar behaviors. The Fermi and anti-Fermi glass transition showing itinerant metallic and insulating conduction properties are also observed at low currents and near critical temperatures.
Memory properties of metal/ferroelectric/semiconductor and metal/ferroelectric/insulator/semiconductor structures using rf sputtered ferroelectric Sr0.8Bi2.5Ta1.2Nb0.8O9 thin films
(2004-07-01)
Huang, CH
;
Wang, YK
;
Lue, HT
;
Huang, JY
;
Lee, MZ
Off-axis rf magnetron sputtering has been employed to grow Sr0.8Bi2.5Ta1.2Nb0.8O9 (SBTN) ferroelectric thin films with (115) preferred orientation on SiO2/Si and Si substrates. The lower temperature and the higher oxygen mixing ratios [OMR, O-2/ (Ar+O-2)] used in film processing lead to reduction in the leakage current densities and widening the memory window of the resultant metal-ferroelectric-insulator semiconductor (MRS) structures. The maximum memory windows of the MFIS structures based on 40% OMR SBTN films deposited at 500 degreesC on SiO2/Si substrate are 2.87 and 2.27 V at the bias amplitudes of 10 and 8 V, respectively. With increasing applied voltage, the memory window also increases. The memory window decreases from 2.27 to 1.59 V after the 10(11) switching cycles at a bias amplitude of 8 V. The capacitance difference, DeltaC, between the two states decreases by 48% after retention time of 7000 s. (C) 2003 Elsevier Ltd. All rights reserved.
Microwave penetration depth measurement for high T-c superconductors by dielectric resonators
(2002-06-01)
Lue, HT
;
Lue, JT
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The penetration depth A(T) dependence on temperatures for high T. superconducting YBa2Cu3O7-delta thin films stored in various environments was measured by a well-designed microwave dielectric resonator. A d-wave T-2 dependence was observed at low temperatures, while an exponential dependence of the penetration depth lambda(T) relevant to the s wave was detected as temperature increases due to thermal fluctuation. An abnormal upturn of the penetration depth at temperatures below 10 K attributed to the surface current carried by the defect surface-induced Andreev bound states can be apparently observed without applying heavy-ion bombardment from this relatively higher frequency measurement. Readers who endeavor to start this kind of measurement can use the well-modified dielectric cavity in conjunction with the detailed measuring procedure.
Photoluminescence and electron paramagnetic resonance studies of defect centers in porous silicon
(2000-06-15)
Lue, HT
;
Huang, BY
;
Lue, JT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Photoluminescence (PL) and electron spin resonance (ESR) spectrometers were exploited to study the Pb defect centers in porous silicon (PS) under various heat treatments. The breaking of Si-H-x and Si-O-H bonds in PS by thermal annealing changes the emission wavelength and increases the recombination centers resulting in degrading the PL intensity. Four kinds of dangling bonds on interfaces of silicon (1 1 1), (1,-1,-1), (-1,1,-1), and (-1,-1,1) faces and SiO2 with C-3V symmetry were identified. The skeleton structure of PS collapsed under thermal annealing. Annealing in hydrogen gas, which is controvertible to the pervasive anticipation, cannot passivate the dangling bonds introduced at high temperatures. (C) 2000 Elsevier Science S.A. All rights reserved.