Browsing by Author "Yang, Che-Yu"

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Application of fluorine doped oxide (SiOF) spacers for improving reliability in low temperature polycrystalline thin film transistors
(2008-12-01)
Feng, Li-Wei
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Tu, Chun-Hao
;
Wu, Yung-Chun
The novel process of self-aligned fluorine doped oxide (SiOF) spacers on low temperature poly-Si (LTPS) lightly doped drain (LDD) thin film transistors (TFTs) is proposed. A fluorine doped oxide spacers were provided to generate the lower dissociation Si-F bonds adjusted to the interface of the drain which is the largest lateral electric field region for lightly doped drain structure. The stronger Si-F bonds can reduce the bonds broken by impact ionization. It is found that the output characteristics of SiOF spacers TFTs show the superior immunity to kink effect. The degradations in Vth shifting, subthreshold slope, drain current and transconductance of SiOF spacers after DC stress are improved. (C) 2008 Elsevier B.V. All rights reserved.
Electrical enhancement of solid phase crystallized poly-Si thin-film transistors with fluorine ion implantation
(2006)
Tu, Chun-Hao
;
Chang, Ting- Chang
;
Liu, Po-Tsun
;
Chen, Chih-Hung
;
Yang, Che-Yu
Solid phase recrystallized polycrystalline silicon thin-film transistors (SPC poly-Si TFTs) with fluorine ion implantation were investigated in this study. Electrical characteristics and reliability of the proposed poly-Si TFTs were improved effectively, especially for field effect mobility and off current. The fluorine-ion-implanted poly-Si TFT can suppress the hot carrier multiplication near the drain side, leading to superior endurance to electrical stress compared with conventional poly-Si TFTs. It was found that fluorine ions will pile up at the poly-Si interface during thermal annealing, without the initial deposition of pad oxide. The proposed technology is manageable and compatible with conventional poly-Si TFT fabrication. As the ion dosages increase more than 5x10(15) cm(-2), however, the electrical characteristics of poly-Si TFTs were degraded due to the increase of trap state density caused by the fluorine segregation in the poly-Si film.
Improved performance of F-ions-implanted poly-Si thin-film transistors using solid phase crystallization and excimer laser crystallization
(2007-03-01)
Tu, Chun-Hao
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Yang, Che-Yu
;
Feng, Li-Wei
Polycrystalline silicon thin-film transistors (Poly-Si TFTs) with F-ions-implantation were investigated in this study. The electrical characteristics and reliability of the F-ions-implanted poly-Si TFTs were reported for solid phase crystallization (SPC) and excimer laser crystallization (ELC) methods respectively. The thermal annealing causes F-ions to pile up at the poly-Si interface, without the initial pad oxide deposition. With the introduction of fluorine in poly-Si film, the trap state density was effectively reduced. Also, the presence of strong Si-F bonds enhances electrical endurance against hot carrier impact by using F-ions-implantation. These improvements in electrical characteristics are even obvious for the ELC poly-Si TFTs compared to the SPC ones.
Performance enhancement of excimer laser crystallized poly-Si thin film transistors with fluorine implantation technology
(2008-03-31)
Tu, Chun-Hao
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Yang, Che-Yu
;
Feng, Li-Wei
Polycrystalline silicon thin film transistors (poly-Si TFTs) with the ion implantation of fluorine elements were investigated in this study. The electrical performance and reliability were reported comprehensively. Experimental work has shown the electrical characteristics of excimer laser crystallized F-ions-implanted poly-Si TFTs are improved effectively, especially for field effect mobility. It is also found that the fluorine piled up at the poly-Si interface during thermal annealing, for the TFT fabricated without a prior deposition of pad oxide. The stronger Si-F bonds replace the Si-Si/Si-H, leading to the superior electrical reliability. However, the dose of F ions is critical in poly-Si, or the electrical characteristics of TFT devices will be degraded. (c) 2007 Published by Elsevier B.V.
Temperature dependence of thin-film transistors electrical characteristics with multiple nano-wire channels
(2005)
Yang, Che-Yu
;
Wu, Yung-Chun
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Chen, Chi-Shen
We have investigated the temperature dependent electrical characteristics of lightly-doped drain (LDD) polysilicon thin-film transistors (poly-Si TFTs) with a series of multi-channel with different widths from 25 degrees C to 175 degrees C. The ten 67 nm-wide spilt channels TFT has best transfer characteristics, because of its robust trigate control and grain boundary defects is the lowest, due to its split nan-wires structure with effective NH3 plasma passivation.