Browsing by Author "Hsu, Wei-Che"

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Anomalous Capacitance Induced by GIDL in P-Channel LTPS TFTs
(2009-11-01)
Lin, Chia-Sheng
;
Chen, Ying-Chung
;
Chang, Ting-Chang
;
Chen, Shih-Ching
;
Jian, Fu-Yen
In this letter, a mechanism of anomalous capacitance in p-channel low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) was investigated. In general, the effective capacitance was only the overlap region and independent with the frequency in LTPS TFTs under the OFF state. However, our experimental results reveal that the capacitance was related with the leakage current and that it was dependent with the measurement frequencies when operated at the OFF-state region. The increase of the capacitance value is verified to be due to the increase of the electron capacitance originating from a gate-induced drain-leakage (GIDL) one. Nevertheless, the GIDL-induced electron capacitance can be suppressed by employing band-to-band hot electron stress.
Degradation of Low Temperature Polycrystalline Silicon Thin Film Transistors under Negative Bias Temperature Instability Stress with Illumination Effect
(2010)
Lin, Chia-Sheng
;
Chen, Ying-Chung
;
Chang, Ting-Chang
;
Li, Hung-Wei
;
Hsu, Wei-Che
This work investigates negative bias temperature instability (NBTI) in low temperature polycrystalline silicon thin film transistors (LTPS TFTs) in a darkened and in an illuminated environment of different light intensities. Experimental results reveal that the generations of interface state density (N(it)) are identical under various illuminated intensity NBTI stresses. Nevertheless, the degradation of the grain boundary trap (N(trap)) under illumination was more significant than that for the darkened environment, with degradation increasing as illumination intensity increases. This phenomenon is mainly caused by the extra number of holes generated during the illuminated NBTI stress. The increased N(trap) degradation leads to an increase in the darkened environment leakage current. This indicates that more traps are generated in the drain junction region than from carrier tunneling via the trap, resulting in leakage current. Conversely, an increase in N(trap) degradation results in a decrease in the photoleakage current. This indicates that the number of recombination centers increases in the poly-Si bulk, affecting photosensitivity in LTPS TFTs.
Hsa-miR-122, a tumor suppressor microRNA that regulates intra-hepatic metastasis of hepatocellular carcinoma
(2009-05-01)
Tsou, Ann-Ping
;
Tsai, Wei-Chih
;
Hsu, Wei-Che
;
Huang, Hsien-Da
;
Chau, Gar-Yang
Illumination-Assisted Negative Bias Temperature Instability Degradation in Low Temperature Polycrystalline Silicon Thin-Film Transistors
(2009)
Lin, Chia-Sheng
;
Chen, Ying-Chung
;
Chang, Ting-Chang
;
Hsu, Wei-Che
;
Chen, Shih-Ching
In this work, the negative bias temperature instability (NBTI) in low temperature polycrystalline silicon thin-film transistors in a darkened and in an illuminated environment was investigated. Experimental results reveal that the generation of interface state density (N(it)) showed no change between the different NBTI stresses. Nevertheless, the degradation of the grain boundary trap (N(trap)) under illumination was more significant than that in the darkened environment. This phenomenon is mainly caused by the extra number of holes generated during the illuminated NBTI stress.
Metallic conduction and large electron-phonon-impurity interference effect in single TiSi nanowires
(2012-09-05)
Hsu, Wei-Che
;
Chen, Chao-Chun
;
Lin, Yong-Han
;
Lin, Huang-Kai
;
Chiu, Hsin-Tien
We report on the first electrical characterizations of single-crystalline TiSi nanowires (NWs) synthesized by chemical vapor deposition reactions. By utilizing the focused-ion-beam-induced deposition technique, we have delicately made four-probe contacts onto individual NWs. The NW resistivities have been measured between 2 and 300 K, which reveal overall metallic conduction with small residual resistivity ratios in the NWs. Surprisingly, we find that the effect due to the interference processes between the elastic electron scattering and the electron-phonon scattering largely dominates over the usual Boltzmann transport even at room temperature. Such prominent electron-phonon-impurity interference effect is ascribed to the presence of large amounts of disorder and high Debye temperatures in TiSi NWs.
NBTI Degradation in LTPS TFTs Under Mechanical Tensile Strain
(2011-07-01)
Lin, Chia-Sheng
;
Chen, Ying-Chung
;
Chang, Ting-Chang
;
Jian, Fu-Yen
;
Hsu, Wei-Che
This letter investigates the negative-bias temperature instability (NBTI) degradation of p-channel low-temperature polycrystalline-silicon thin-film transistors (LTPS TFTs) under mechanical tensile stress. Experimental results reveal that the interface state density N(it) and grain boundary trap density N(trap) of tensile-strained LTPS TFTs are more pronounced than those of unstrained LTPS TFTs. Extracted density of states and conduction activation energy E(a) both show increases due to the strained Si-Si bonds, which implies that strained Si-Si bonds are able to react with dissociated H during NBTI stress. Therefore, NBTI degradation is more significant after tensile strain than in an unstrained condition.
Transient Effect Assisted NBTI Degradation in p-Channel LTPS TFTs under Dynamic Stress
(2011)
Lin, Chia-Sheng
;
Chen, Ying-Chung
;
Chang, Ting-Chang
;
Li, Hung-Wei
;
Chen, Shih-Ching
This work investigates dynamic negative bias temperature instability (NBTI) in p-channel low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) with different rise and fall times. Experimental results reveal identical increases in the interface state density (N(it)) induced by different dynamic NBTI stress conditions. Nevertheless, the degradation of the grain boundary trap (N(trap)) becomes more significant as rise time decreases to 1 mu s. Because the surface inversion layer cannot form during the short rise time, transient bulk voltage will cause excess holes to diffuse into the poly-Si bulk. Therefore, the significant N(trap) increase is assisted by this transient effect. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3507253] All rights reserved.