Browsing by Author "Lee, Ming-Hsien"

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Analysis of Degradation Mechanism in SONOS-TFT Under Hot-Carrier Operation
(2010-12-01)
Chen, Te-Chih
;
Chang, Ting-Chang
;
Chen, Shih-Ching
;
Hsieh, Tien-Yu
;
Jian, Fu-Yen
This letter investigates the degradation mechanism of polycrystalline silicon thin-film transistors with a silicon-oxide-nitride-oxide-silicon structure under OFF-state stress. During the electrical stress, the hot hole generated from band-to-band tunneling process will inject into gate dielectric, and the significant ON-state degradation (more than 1 order) indicates that the interface states are accompanied with hot-hole injection. In addition, the asymmetric I-V characteristics indicate that the interface states are located near the drain side. Moreover, the ISE-TCAD simulation tool was utilized to model the degradation mechanism and analyze trap states distribution. Although both the vertical and lateral electrical fields are factors for degradation and hot-hole injection, the degradation is mainly affected by the lateral electrical field over a critical point.
Charge-Trapping-Induced Parasitic Capacitance and Resistance in SONOS TFTs Under Gate Bias Stress
(2011-03-01)
Lin, Chia-Sheng
;
Chen, Ying-Chung
;
Chang, Ting-Chang
;
Jian, Fu-Yen
;
Li, Hung-Wei
This letter investigates the charge-trapping-induced parasitic resistance and capacitance in silicon-oxide-nitride-oxide-silicon thin-film transistors under positive and negative dc bias stresses. The results identify a parasitic capacitance in OFF-state C-V curve caused by electrons trapped in the gate insulator near the defined gate region during the positive stress, as well as the depletion induced by those trapped electrons. Meanwhile, the induced depletions in source/drain also degraded the I-V characteristic when the gate bias is larger than the threshold voltage. However, these degradations slightly recover when the trapped electrons are removed after negative bias stress. The electric field in the undefined gate region is also verified by TCAD simulation software.
Effect of Lateral Body Terminal on Silicon-Oxide-Nitride-Oxide-Silicon Thin-Film Transistors
(2011-10-01)
Li, Hung-Wei
;
Chang, Ting-Chang
;
Chang, Geng-Wei
;
Lin, Chia-Sheng
;
Tsai, Tsung-Ming
We investigate lateral-body-terminal silicon-oxide-nitride-oxide-silicon thin-film transistors (LBT SONOS TFTs) under erasing operation. These devices have superior erasing efficiency by gate as well as lateral body electrode exerting bias. The erasing mechanism of LBT SONOS TFTs has been illustrated by the energy band diagrams. Holes gain sufficient energy by the electric field in the deep-depletion region to surmount the tunneling oxide barrier because of exerting body bias under erasing operation. In addition, the lateral body terminal exerting bias can enhance the erasing efficiency and is confirmed by different erasing conditions and structures. In addition, to verify the hole current injecting from the lateral body site, the size effect of LBT SONOS TFTs is also discussed.
Effective density-of-states distribution of polycrystalline silicon thin-film transistors under hot-carrier degradation
(2007-09-01)
Lee, Ming-Hsien
;
Chang, Kai-Hsiang
;
Lin, Horng-Chih
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this work, quantitative information for nonuniform hot-carrier degradation, especially under mild stressing condition, is investigated. A test structure capable of revealing hot-carrier degradations of polycrystalline silicon (poly-Si) thin-film transistors in specific portions of the channel is employed. Effective density-of-states (DOS) distributions at the damaged sites can be extracted using field-effect conductance method, thus providing an effective tool to evaluate the impact of hot-carrier degradations. By measuring along individual sections of the channel, it becomes possible to extract the DOS for the device as a whole. The combination of the proposed test structure and DOS extraction technique also provides a powerful tool for modeling and simulating current-voltage characteristics of thin-film transistors under hot-carrier stressing. (c) 2007 American Institute of Physics.
Fabrication and characterization of nanowire transistors with solid-phase crystallized poly-Si channels
(2006-10-01)
Lin, Horng-Chih
;
Lee, Ming-Hsien
;
Su, Chun-Jung
;
Shen, Shih-Wen
;
電子工程學系及電子研究所
The performance of thin-film transistors with a novel poly-Si nanowire channel prepared by solid-phase crystallization is investigated in this paper. As compared with conventional planar devices having self-aligned source/drain, the new devices show an improved ON-current per unit width and better control over the short channel effects. The major conduction mechanism of the OFF-state leakage is identified as the gate-induced drain leakage, and it is closely related to the source/drain implant condition and the unique device structure.
First Principles Calculations of Linear and Second-Order Optical Responses in Rhombohedrally Distorted Perovskite Ternary Halides, CsGeX(3) (X = Cl, Br, and I)
(2009-11-01)
Tang, Li-Chuan
;
Chang, Yia-Chung
;
Huang, Jung-Yau
;
Lee, Ming-Hsien
;
Chang, Chen-Shiung
Systematic studies based on first-principles calculations of second. order optical susceptibilities as well as the dielectric function of CsGeX(3) (X = Cl Br, and I, CGX) are presented The relationship between structural properties and optoelectronic responses are examined The structural factors Delta alpha, and d(Ge), d(x) are proposed to describe the degree of distortion from an ideal perovskite structure. Delta alpha and dGe increase when halide anions are changed from Cl to I, while halide anion displacement, dx, decreases. The structural distortion effect on these rhombohedral CGX crystals is analyzed by first-principles calculations The dielectric function and the second harmonic generation (SHG) response coefficient also increase with increasing Delta alpha and d(Ge). The direct band gaps (E(c)) of CsGeX3 ail occur at the R-point, Delta E(R) The experimental band gaps of CGX crystals become smaller. i e, E(G)(CGI) (= 3 67eV) > E(G)(CGB) (=2 32 eV) > E(G)(CGI) (= 1 53eV), as Delta alpha and el increase, i e. d(Ge)(CGC) < d(Ge)(CGR) < d(GB)(CGI) Partial density of states (PDOS) analysis revealed that the valence band maximum (VBM) and conduction band minimum (CBM) are mainly contributed by the p-orbitals of germanium. The calculated magnitudes of chi((2))(ijk) are close to some reported experimental values near the band gap (C) 2009 The Japan Society of Applied Physics
First Principles Calculations of Linear and Second-Order Optical Responses in Rhombohedrally Distorted Perovskite Ternary Halides, CsGeX3 (X = Cl, Br, and I)
(2009-11-01)
Tang, Li-Chuan
;
Chang, Yia-Chung
;
Huang, Jung-Yau
;
Lee, Ming-Hsien
;
Chang, Chen-Shiung
Systematic studies based on first-principles calculations of second. order optical susceptibilities as well as the dielectric function of CsGeX3 (X = Cl Br, and I, CGX) are presented The relationship between structural properties and optoelectronic responses are examined The structural factors Delta alpha, and d(Ge), d(x) are proposed to describe the degree of distortion from an ideal perovskite structure. Delta alpha and dGe increase when halide anions are changed from Cl to I, while halide anion displacement, dx, decreases. The structural distortion effect on these rhombohedral CGX crystals is analyzed by first-principles calculations The dielectric function and the second harmonic generation (SHG) response coefficient also increase with increasing Delta alpha and d(Ge). The direct band gaps (E-c) of CsGeX3 ail occur at the R-point, Delta E-R The experimental band gaps of CGX crystals become smaller. i e, E-G(CGI) (= 3 67eV) > E-G(CGB) (=2 32 eV) > E-G(CGI) (= 1 53eV), as Delta alpha and el increase, i e. d(Ge)(CGC) < d(Ge)(CGR) < d(GB)(CGI) Partial density of states (PDOS) analysis revealed that the valence band maximum (VBM) and conduction band minimum (CBM) are mainly contributed by the p-orbitals of germanium. The calculated magnitudes of chi((2))(ijk) are close to some reported experimental values near the band gap (C) 2009 The Japan Society of Applied Physics
Spatially and temporally resolving the degradation of n-channel poly-Si thin-film transistors under hot-carrier stressing
(2007-03-01)
Lee, Ming-Hsien
;
Chang, Kai-Hsiang
;
Lin, Horng-Chih
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A test structure was proposed to investigate the spatial and temporal evolution of hot-carrier degradation in n-channel poly-Si thin-film transistors. Our experimental results clearly show that the initial damage during the early stage of hot-carrier stressing, which is still undetectable by conventional test structures, can be easily observed by the structure. In addition, the proposed test structure is also capable of resolving the evolution of the degradation along the channel, thus providing a powerful tool to study the location-dependent damage mechanisms. (c) 2007 American Institute of Physics.
Spatially resolving the degradation of SPC thin-film transistors under AC stress
(2007)
Chang, Kai-Hsiang
;
Lee, Ming-Hsien
;
Lin, Horng-Chih
;
Huang, Tiao-Yuan
;
Lee, Yao-Jen
Unusual Threshold Voltage Shift Caused by Self-Heating-Induced Charge Trapping Effect
(2010)
Jian, Fu-Yen
;
Chang, Ting-Chang
;
Chu, An-Kuo
;
Chen, Te-Chih
;
Chen, Shih-Ching
This article investigates the threshold voltage (V(t)) shift induced by a self-heating effect for n-channel low temperature poly-Si thin film transistors (TFTs) and finds that there is a shift of more than 3 V in the negative direction after a self-heating operation of 100 ms. The negative V(t) shift can be attributed to the charge-trapping effect caused by the holes generated by trap-assisted band-to-band thermionic field emission and trapped in the grain boundary of the poly-Si film substrate. We used lateral body contact structure to verify that this unusual V(t) shift is related to the holes trapped in the substrate. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3290686] All rights reserved.