Browsing by Issue Date, starting with "2011-01-17"

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Constant voltage stress induced charge trapping and detrapping characteristics of the Si3N4 uniaxial strained n-channel metal-oxide-semiconductor field-effect-transistor with fluorinated HfO2/SiON gate stack
(2011-01-17)
Chen, Yung-Yu
;
Hsieh, Chih-Ren
;
Chiu, Fang-Yu
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Charge trapping and detrapping characteristics of Si3N4 contact etch stop layer (SiN CESL) uniaxial strained n-channel metal-oxide-semiconductor field-effect-transistor (nMOSFET) with fluorinated HfO2/SiON gate stack have been investigated for the first time. Smaller threshold voltage shift can consequently obtain for the SiN CESL strained nMOSFET with fluorinated HfO2/SiON gate stack, primarily due to passivation of oxygen vacancies and dangling bonds by either nitrogen or fluorine atoms. However, the SiN CESL strained nMOSFET with fluorinated gate stack inevitably exhibits less charge detrapping ratio, which means greater part of stress-induced charges would remain in the gate stack after nitrogen or fluorine incorporation, respectively. (c) 2011 American Institute of Physics. [doi:10.1063/1.3541878]
Constant voltage stress induced charge trapping and detrapping characteristics of the Si(3)N(4) uniaxial strained n-channel metal-oxide-semiconductor field-effect-transistor with fluorinated HfO(2)/SiON gate stack
(2011-01-17)
Chen, Yung-Yu
;
Hsieh, Chih-Ren
;
Chiu, Fang-Yu
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Charge trapping and detrapping characteristics of Si(3)N(4) contact etch stop layer (SiN CESL) uniaxial strained n-channel metal-oxide-semiconductor field-effect-transistor (nMOSFET) with fluorinated HfO(2)/SiON gate stack have been investigated for the first time. Smaller threshold voltage shift can consequently obtain for the SiN CESL strained nMOSFET with fluorinated HfO(2)/SiON gate stack, primarily due to passivation of oxygen vacancies and dangling bonds by either nitrogen or fluorine atoms. However, the SiN CESL strained nMOSFET with fluorinated gate stack inevitably exhibits less charge detrapping ratio, which means greater part of stress-induced charges would remain in the gate stack after nitrogen or fluorine incorporation, respectively. (c) 2011 American Institute of Physics. [doi:10.1063/1.3541878]
Accelerated quark and holography for confining gauge theory
(2011-01-18)
Ghoroku, Kazuo
;
Ishihara, Masafumi
;
Kubo, Kouki
;
Taminato, Tomoki
;
電子物理學系
We show a constantly accelerated quark as a string solution of the Nambu-Goto action, which is embedded in the bulk background dual to the N = 2 supersymmetric confining Yang-Mills theory. The induced metric of the world sheet for this string solution has an event horizon specified by the fifth coordinate. By an extended Rindler transformation proposed by Xiao, we move to the comoving frame of the accelerated quark string. Then we find that this horizon is transferred to the event horizon of the bulk and the causal part of the accelerated quark is transformed to a static free quark in the Rindler coordinate. As a result, the confinement of the Minkowski vacuum is lost in the Rindler vacuum. This point is assured also by studying the potential between the quark and antiquark. However, the remnants of the original confining force are seen in various thermal quantities. We also discuss the consistency of our results and the claim that the Green's functions will not be changed by the Rindler transformation.
First-principles calculations of engineered surface spin structures
(2011-01-18)
Lin, Chiung-Yuan
;
Jones, B. A.
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The engineered spin structures recently built and measured in scanning tunneling microscope experiments are calculated using density functional theory. By determining the precise local structure around the surface impurities, we find that the Mn atoms can form molecular structures with the binding surface, behaving like surface molecular magnets. The spin structures are confirmed to be antiferromagnetic, and the exchange couplings are calculated within 8% of the experimental values simply by collinear-spin generalized gradient approximation +U calculations. We can also explain why the exchange couplings significantly change with different impurity binding sites from the determined local structure. The bond polarity is studied by calculating the atomic charges with and without the Mn adatoms. In addition, we study a second adatom, Co. We study the surface Kondo effect of Co by calculating the surrounding local density of states and the on-site Coulomb U and compare and contrast the behavior of Co and Mn. Finally, our calculations confirm that the Mn and Co spins of these structures are 5/2 and 3/2, respectively, as also measured indirectly by scanning tunneling microscope.
Heterogeneous and Homogeneous Nucleation of Epitaxial NiSi(2) in [110] Si Nanowires
(2011-01-20)
Chou, Yi-Chia
;
Wu, Wen-Wei
;
Lee, Chung-Yang
;
Liu, Chun-Yi
;
Chen, Lih-Juann
We report here both heterogeneous and homogeneous nucleation of epitaxial suicide of NiSi(2) in Si nanowires grown in [110] direction by in situ observation in high-resolution transmission electron microscopy (TEM). Owing to the excellent lattice match between Si and NiSi(2), a giant epitaxial step of 2-8 nm wide forms at the interface between Si and NiSi(2) during the growth of the latter. The step formation results in two suicide/Si interfaces parallel to each other in TEM observations. Heterogeneous nucleation of NiSi(2) occurs at the intersection where the step meets the interfaces. However, we have also observed the epitaxial growth of NiSi(2) having a single interface with the Si, i.e., without a giant step. Homogeneous nucleation of NiSi(2) occurs on the single interface. Incubation time of heterogeneous nucleation of NiSi(2) has been measured by high-resolution video to be much shorter than that of homogeneous nucleation. The overall growth rate of NiSi(2) for the case of heterogeneous nucleation is faster than that for the case of homogeneous nucleation. Kinetic analysis of both types of nucleation is presented for a direct comparison in order to have a better understanding of the nucleation events.
Heterogeneous and Homogeneous Nucleation of Epitaxial NiSi2 in [110] Si Nanowires
(2011-01-20)
Chou, Yi-Chia
;
Wu, Wen-Wei
;
Lee, Chung-Yang
;
Liu, Chun-Yi
;
Chen, Lih-Juann
We report here both heterogeneous and homogeneous nucleation of epitaxial suicide of NiSi2 in Si nanowires grown in [110] direction by in situ observation in high-resolution transmission electron microscopy (TEM). Owing to the excellent lattice match between Si and NiSi2, a giant epitaxial step of 2-8 nm wide forms at the interface between Si and NiSi2 during the growth of the latter. The step formation results in two suicide/Si interfaces parallel to each other in TEM observations. Heterogeneous nucleation of NiSi2 occurs at the intersection where the step meets the interfaces. However, we have also observed the epitaxial growth of NiSi2 having a single interface with the Si, i.e., without a giant step. Homogeneous nucleation of NiSi2 occurs on the single interface. Incubation time of heterogeneous nucleation of NiSi2 has been measured by high-resolution video to be much shorter than that of homogeneous nucleation. The overall growth rate of NiSi2 for the case of heterogeneous nucleation is faster than that for the case of homogeneous nucleation. Kinetic analysis of both types of nucleation is presented for a direct comparison in order to have a better understanding of the nucleation events.
自己整合薄膜トランジスタの製造方法とその構造体
(2011-01-20)
周政偉
;
冉暁▲ブン▼
;
蔡娟娟
【課題】自己整合薄膜トランジスタ（ＴＦＴ）の製造方法を提供する。【解決手段】先ず、透明基板の第１表面上に酸化物ゲート、誘電体層、及びフォトレジスト層を順に堆積する。次に、該透明基板の第１表面と反対側の第２表面に紫外光を照射することで、該フォトレジスト層を露光する。この時、該酸化物ゲートからなるゲートはマスクとして働き、該フォトレジスト層の該酸化物ゲートに対応する部分に照射される紫外光を吸収する。次に、該露光されたフォトレジスト層を除去し、該フォトレジスト層の未露光部分と該誘電体層との上に透明導電層を堆積する。次に、該透明導電層にパターン形成プロセスを実行して、ソースとドレインとを形成し、ソース、ドレイン、及び誘電体層を覆うようアクティブ層を形成して、自己整合ＴＦＴ構造体が完成する。【選択図】図１
Drug Delivery Nanodevice, its Preparation Method and Uses Thereof
(2011-01-20)
Chen, San-Yuan
;
Hu, Shang-Hsiu
;
Liu, Dean-Mo
;
Kuo, Kun-Ting
Nanodevice and method for in vivo monitoring and release of drugs are provided. The disclosed nanodevice is characterized in having a drug-loaded nanosphere that is capable of releasing the encapsulated drugs upon magnetically stimulation. The nanodevice may also be used as a contrast agent for in vivo imaging and monitoring the concentration and distribution of the released drugs and/or active compounds injected separately into a target site of a subject.
Direct spectroscopic evidence of charge reversal at the Pb(Zr(0.2)Ti(0.8))O(3)/La(0.7)Sr(0.3)MnO(3) heterointerface
(2011-01-21)
Wu, Chung-Lin
;
Lee, Pei-Wei
;
Chen, Yi-Chun
;
Chang, Lo-Yueh
;
Chen, Chia-Hao
At the heterointerface of a top ferroelectric Pb(Zr(0.2)Ti(0.8))O(3) (PZT) ultrathin film and a bottom La(0.7)Sr(0.3)MnO(3) (LSMO) electrode, we used continuous synchrotron-radiation photoelectron spectroscopy to probe in situ and demonstrated that the interfacial charges are reversible and their affected valence-band barrier height becomes modulated upon switching the polarization in the top layer. By monitoring the core-level shifting of the buried LSMO layer under continuous illumination of synchrotron radiation, we directly observed a temporal screening of polarization induced by the photon-generated carriers in the top PZT layer. This dynamic characterization of the core-level shifting of the buried layer demonstrates an effective method to probe the electric conduction and ferroelectric polarization of an ultrathin ferroelectric oxide thin film.
Direct spectroscopic evidence of charge reversal at the Pb(Zr0.2Ti0.8)O-3/La0.7Sr0.3MnO3 heterointerface
(2011-01-21)
Wu, Chung-Lin
;
Lee, Pei-Wei
;
Chen, Yi-Chun
;
Chang, Lo-Yueh
;
Chen, Chia-Hao
At the heterointerface of a top ferroelectric Pb(Zr0.2Ti0.8)O-3 (PZT) ultrathin film and a bottom La0.7Sr0.3MnO3 (LSMO) electrode, we used continuous synchrotron-radiation photoelectron spectroscopy to probe in situ and demonstrated that the interfacial charges are reversible and their affected valence-band barrier height becomes modulated upon switching the polarization in the top layer. By monitoring the core-level shifting of the buried LSMO layer under continuous illumination of synchrotron radiation, we directly observed a temporal screening of polarization induced by the photon-generated carriers in the top PZT layer. This dynamic characterization of the core-level shifting of the buried layer demonstrates an effective method to probe the electric conduction and ferroelectric polarization of an ultrathin ferroelectric oxide thin film.
Solute-solvent intermolecular vibronic coupling as manifested by the molecular near-field effect in resonance hyper-Raman scattering
(2011-01-21)
Shimada, Rintaro
;
Hamaguchi, Hiro-o
;
應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
Vibronic coupling within the excited electronic manifold of the solute all-trans-beta-carotene through the vibrational motions of the solvent cyclohexane is shown to manifest as the "molecular near-field effect," in which the solvent hyper-Raman bands are subject to marked intensity enhancements under the presence of all-trans-beta-carotene. The resonance hyper-Raman excitation profiles of the enhanced solvent bands exhibit similar peaks to those of the solute bands in the wavenumber region of 21 700-25 000 cm(-1) (10 850-12 500 cm(-1) in the hyper-Raman exciting wavenumber), where the solute all-trans-beta-carotene shows a strong absorption assigned to the 1A(g) -> 1B(u) transition. This fact indicates that the solvent hyper-Raman bands gain their intensities through resonances with the electronic states of the solute. The observed excitation profiles are quantitatively analyzed and are successfully accounted for by an extended vibronic theory of resonance hyper-Raman scattering that incorporates the vibronic coupling within the excited electronic manifold of all-trans-beta-carotene through the vibrational motions of cyclohexane. It is shown that the major resonance arises from the B-term (vibronic) coupling between the first excited vibrational level (v = 1) of the 1B(u) state and the ground vibrational level (v = 0) of a nearby A(g) state through ungerade vibrational modes of both the solute and the solvent molecules. The inversion symmetry of the solute all-trans-beta-carotene is preserved, suggesting the weak perturbative nature of the solute-solvent interaction in the molecular near-field effect. The present study introduces a new concept, " intermolecular vibronic coupling," which may provide an experimentally accessible/theoretically tractable model for understanding weak solute-solvent interactions in liquid. (C) 2011 American Institute of Physics. [doi:10.1063/1.3512923]
空時編碼／正交分頻多工系統中合併通道估計與資料偵測方法
(2011-01-21)
古孟霖
;
黃家齊
本發明係以最佳化方法合併通道估計及資料偵測，利用資料子載波與稀疏領航子載波追蹤通道變化；其特徵在於使用牛頓法及資料子載波達到合併通道估計及資料偵測之最佳化，並利用稀疏領航子載波所形成之最大相似函數之一階部分微分方向向量做為通道估計器追蹤通道變化之初始參考方向以得到更好的通道估計。本發明在高車行速度及大通道延遲環境下具有良好系統效能表現。
交大e-News第087期
(2011-01-21)
Secretariat
;
國立交通大學秘書室
Integration structure of semiconductor circuit and microprobe sensing elements and method for fabricating the same
(2011-01-25)
Chiou
;
Jin-Chern
;
Chang
;
Chih-Wei
The present invention discloses an integration structure of a semiconductor circuit and microprobe sensing elements and a method for fabricating the same. In the method of the present invention, a semiconductor circuit is fabricated on one surface of a semiconductor substrate, and the other surface of the semiconductor substrate is etched to form a microprobe structure for detect physiological signals. Next, a deposition method is used to sequentially form an electrical isolated layer and an electrical conductive layer on the microprobes. Then, an electrical conductive material is used to electrically connect the electrical conductive layer with the electrical pads of the semiconductor circuit. Thus is achieved the integration of a semiconductor circuit and microprobe sensing elements in an identical semiconductor substrate with the problem of electric electrical isolated being solved simultaneously. Thereby, the voltage level detected by the microprobes will not interfere with the operation of the semiconductor circuit.
Seebeck coefficients in nanoscale junctions: Effects of electron-vibration scattering and local heating
(2011-01-25)
Hsu, Bailey C.
;
Liu, Yu-Shen
;
Lin, Sheng Hsien
;
Chen, Yu-Chang
;
電子物理學系
We report first-principles calculations of inelastic Seebeck coefficients in an aluminum monatomic junction. We compare the elastic and inelastic Seebeck coefficients with and without local heating. In the low-temperature regime, the signature of normal modes in the profiles of the inelastic Seebeck effects is salient. The inelastic Seebeck effects are enhanced by the normal modes and further magnified by local heating. In the high-temperature regime, the inelastic Seebeck effects are weakly suppressed due to the quasiballistic transport.
Investigation of low-temperature electroluminescence of InGaN/GaN based nanorod light emitting arrays
(2011-01-28)
Huang, Ying-Yuan
;
Chen, Liang-Yi
;
Chang, Chun-Hsiang
;
Sun, Yu-Hsuan
;
Cheng, Yun-Wei
For InGaN/GaN based nanorod devices using a top-down etching process, the optical output power is affected by non-radiative recombination due to sidewall defects (which decrease light output efficiency) and the mitigated quantum confined Stark effect (QCSE) due to strain relaxation (which increases internal quantum efficiency). Therefore, the exploration of low-temperature optical behaviors of nanorod light emitting diodes (LEDs) will help identify the correlation between these two factors. In this work, low-temperature electroluminescent (EL) spectra of InGaN/GaN nanorod arrays were explored and compared with those of planar LEDs. The nanorod LED exhibits a much higher optical output percentage increase when the temperature decreases. The increase is mainly attributed to the increased carriers in the quantum wells for radiative recombination. Also, due to a better spatial overlap of electrons and holes in the quantum wells, the increased number of carriers can be more efficiently recombined in the nanorod device. Next, while the nanorod array shows nearly constant peak energy in the EL spectra at various injection currents at the temperature of 300 K, a blue shift has been observed at 190 K. The results suggest that with less non-radiative recombination and thus more carriers in the quantum wells, carrier screening and band filling still prevail in the partially strain relaxed nanorods. Moreover, when the temperature drops to 77 K, the blue shift of both nanorod and planar devices disappears and the optical output power decreases since there are fewer carriers in the quantum wells for radiative recombination.
Association structures of ionic liquid/DMSO mixtures studied by high-pressure infrared spectroscopy
(2011-01-28)
Jiang, Jyh-Chiang
;
Lin, Kuan-Hung
;
Li, Sz-Chi
;
Shih, Pao-Ming
;
Hung, Kai-Chan
Using high-pressure infrared methods, we have investigated close interactions of charge-enhanced C-H-O type in ionic liquid/dimethyl sulfoxide (DMSO) mixtures. The solvation and association of the 1-butyl-3-methylimidazolium tetrafluoroborate (BMI(+)BF(4)(-)) and 1-butyl-2,3-dimethylimidazolium tetrafluoroborate (BMM(+)BF(4)(-)) in DMSO-d(6) were examined by analysis of C-H spectral features. Based on our concentration-dependent results, the imidazolium C-H groups are more sensitive sites for C-H-O than the alkyl C-H groups and the dominant imidazolium C-H species in dilute ionic liquid/DMSO-d(6) should be assigned to the isolated (or dissociated) structures. As the dilute mixtures were compressed by high pressures, the loss in intensity of the bands attributed to the isolated structures was observed. In other words, high pressure can be used to perturb the association-dissociation equilibrium in the polar region. This result is remarkably different from what is revealed for the imidazolium C-H in the BMM(+)BF(4)(-)/D(2)O mixtures. DFT-calculations are in agreement with our experimental results indicating that C(4)-H-O and C(5)-H-O interactions seem to play non-negligible roles for BMM(+)BF(4)(-)/DMSO mixtures. (C) 2011 American Institute of Physics. [doi:10.1063/1.3526485]
Molecular structural property and potential energy dependence on nonequilibrium-thermodynamic state point of liquid n-hexadecane under shear
(2011-01-28)
Tseng, Huan-Chang
;
Chang, Rong-Yeu
;
Wu, Jiann-Shing
;
應用化學系
;
Department of Applied Chemistry
Extensive computer experiments have been conducted in order to shed light on the macroscopic shear flow behavior of liquid n-hexadecane fluid under isobaric-isothermal conditions through the nonequilibrium molecular dynamic methodology. With respect to shear rates, the accompanying variations in structural properties of the fluid span the microscopic range of understanding from the intrinsic to extrinsic characteristics. As drawn from the average value of bond length and bond angle, the distribution of dihedral angle, and the radius distribution function of intramolecular and intermolecular van der Waals distances, these intrinsic structures change with hardness, except in the situation of extreme shear rates. The shear-induced variation of thermodynamic state curve along with the shear rate studied is shown to consist of both the quasiequilibrium state plateau and the nonequilibrium-thermodynamic state slope. Significantly, the occurrence of nonequilibrium-thermodynamic state behavior is attributed to variations in molecular potential energies, which include bond stretching, bond bending, bond torsion, and intra-and intermolecular van der Waals interactions. To unfold the physical representation of extrinsic structural deformation, under the aggressive influence of a shear flow field, the molecular dimension and appearance can be directly described via the squared radius of gyration and the sphericity angle, R(g)(2) and phi, respectively. In addition, a specific orientational order S(x) defines the alignment of the molecules with the flow direction of the x-axis. As a result, at low shear rates, the overall molecules are slightly stretched and shaped in a manner that is increasingly ellipsoidal. Simultaneously, there is an obvious enhancement in the order. In contrast to high shear rates, the molecules spontaneously shrink themselves with a decreased value of R(g)(2), while their shape and order barely vary with an infinite value of phi and S(x). It is important to note that under different temperatures and pressures, these three parameters are integrated within a molecular description in response to thermodynamic state variable of density and rheological material function of shear viscosity. (C) 2011 American Institute of Physics. [doi:10.1063/1.3541825]
Compact microdisk cavity laser with type-II GaSb/GaAs quantum dots
(2011-01-31)
Hsu, K. S.
;
Chiu, T. T.
;
Lin, Wei-Hsun
;
Chen, K. L.
;
Shih, M. H.
Microdisk lasers with active region made of type-II GaSb/GaAs quantum dots on the GaAs substrate have been demonstrated. A microdisk cavity with diameter of 3.9 mu m was fabricated from a 225-nm-thick GaAs layer filled with GaSb quantum dots. Lasing at wavelengths near 1000 nm at 150 K was achieved for this microdisk. A high threshold characteristic temperature of 77 K was also observed. It is found that the lasing wavelength matches closely with the first-order whispering-gallery mode of the cavity as obtained from the finite-element method simulation. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3543839]
A reflective polarizer-free electro-optical switch using dye-doped polymer-stabilized blue phase liquid crystals
(2011-01-31)
Lin, Yi-Hsin
;
Chen, Hung-Shan
;
Chiang, Tsung-Han
;
Wu, Chun-Hung
;
Hsu, Hsu-Kuan
We demonstrate a reflective polarizer-free electro-optical switch using dye-doped polymer-stabilized blue phase liquid crystals (DDPSBP-LC). At the voltage-off state, the dye molecules and liquid crystals form the structure of the double twist cylinders. As a result, the DDPSBP-LC is in dark state due to the combination of Bragg reflection and light absorption. At the voltage-on state, the blue phase structure is unwound locally. The DDPSBP-LC is then in bright state because of the small light absorption only. The applications of such a switch are shutter glass of 3D displays, and electronic papers. (C) 2011 Optical Society of America