Browsing by Author "Wei, Kai-Fang"

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Fabrication and characterization of excimer laser crystallized double-gate low-temperature poly-silicon thin film transistors
(2007)
Tsai, Chun-Chien
;
Wei, Kai-Fang
;
Lee, Yao-Jen
;
Lee, I-Che
;
Chen, Hsu-Hsin
In this letter, high-performance low-temperature poly-Silicon (LTPS) thin film transistors (TFTs) with double-gate (DG) structure and lateral silicon grains have been demonstrated by excimer laser crystallization (ELC). Therefore, the proposeed ELC DG TFTs exhibited better current-voltage characteristics as compared with the conventional solid-phase crystallized (SPC) poly-Si double-gate TFTs or conventional ELC top-gate (TG) TFTs.
High-performance short-channel double-gate low-temperature polysilicon thin-film transistors using excimer laser crystallization
(2007-11-01)
Tsai, Chun-Chien
;
Wei, Kai-Fang
;
Lee, Yao-Jen
;
Chen, Hsu-Hsin
;
Wang, Jyh-Liang
In this letter, high-performance low-temperature polysilicon thin-film transistors (TFTs) with double-gate (DG) structure and controlled lateral grain growth have been demonstrated by excimer laser crystallization. Via a proper excimer laser condition, along with the a-Si step height beside the bottom gate, a superlateral growth of Si was formed in the channel length plateau. Therefore, the DG TFTs with lateral silicon grains in the channel regions exhibited better current-voltage characteristics, as compared with the conventional top-gate ones. The proposed DG TFTs (W/L = 1/1 mu m) had the field-effect mobility exceeding 550 cm(2)/V . s, an ON/OFF current ratio that is higher than 10(8), superior short-channel characteristics, and higher current drivability. In addition, the device-to-device uniformity could be improved since grain growth could be artificially controlled by the spatial plateau structure.
High-performance top and bottom double-gate low-temperature poly-silicon thin film transistors fabricated by excimer laser crystallization
(2008-03-01)
Tsai, Chun-Chien
;
Lee, Yao-Jen
;
Wang, Jyh-Liang
;
Wei, Kai-Fang
;
Lee, I-Che
In this work, high-performance low-temperature poly-silicon (LTPS) thin film transistors (TFTs) with double-gate (DG) structure and lateral grain growth have been demonstrated by excimer laser crystallization (ELC). Therefore, the DG TFTs with lateral silicon grains in the channel regions exhibited better current-voltage characteristics as compared with the conventional solid-phase crystallized (SPC) poly-Si double-gate TFTs or conventional ELC top-gate (TG) TFTs. The proposed ELC DG TFTs (W/L = 1.5/1.5 mu m) had the field-effect-mobility exceeding 400 cm(2)/V s, on/off current ratio higher than 10(8), superior short-channel characteristics and higher current drivability. (c) 2007 Elsevier Ltd. All rights reserved.
Investigation of source-follower type analog buffer using low temperature poly-Si TFTs
(2007-03-01)
Chen, Bo-Ting
;
Tai, Ya-Hsiang
;
Wei, Ying-Jyun
;
Wei, Kai-Fang
;
Tsai, Chun-Chien
A new source follower circuit using low-temperature polycrystalline silicon thin film transistors (LTPS-TFTs) as analog buffer for the integrated data driver circuit of active matrix liquid crystal displays (AMLCDs) and active matrix light emitting diodes (AMOLEDs) is proposed and measured. Threshold voltage compensation circuit with two n-type thin film transistors, a capacitor, and four switches structure is used to enhance image quality for the display. The threshold voltage difference of driving TFTs and the unsaturated of output voltage are eliminated in this circuit. An active load is added and a calibration operation is applied to study the effects on the source follower circuit, the transistor operation mode region is also discussed. The proposed circuit is capable of minimizing the variation from both the signal timing and the device characteristics through the simulation and measured results. (C) 2007 Elsevier Ltd. All rights reserved.
Polycrystalline silicon thin-film transistors with location-controlled crystal grains fabricated by excimer laser crystallization
(2007-11-12)
Tsai, Chun-Chien
;
Lee, Yao-Jen
;
Chiang, Ko-Yu
;
Wang, Jyh-Liang
;
Lee, I-Che
In this paper, location-controlled silicon crystal grains are fabricated by the excimer laser crystallization method which employs amorphous silicon spacer structure and prepatterned thin films. The amorphous silicon spacer in nanometer-sized width formed using spacer technology is served as seed crystal to artificially control superlateral growth phenomenon during excimer laser irradiation. An array of 1.8-mu m-sized disklike silicon grains is formed, and the n-channel thin-film transistors whose channels located inside the artificially-controlled crystal grains exhibit higher performance of field-effect-mobility reaching 308 cm(2)/V s as compared with the conventional ones. This position-manipulated silicon grains are essential to high-performance and good uniformity devices. (c) 2007 American Institute of Physics.