Browsing by Author "Tsai, Chia-Chou"

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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.
Formation of germanium nanocrystals embedded in silicon-oxygen-nitride layer
(2006-07-31)
Tu, Chun-Hao
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Liu, Hsin-Chou
;
Tsai, Chia-Chou
The formation of germanium nanocrystals embedded in silicon-oxygen nitride with distributed charge storage elements is proposed in this work. A large memory window is observed due to isolated Ge nanocrystals in the SiON gate stack layer. The Ge nanocrystals were nucleated after high temperature oxidized SiGeN layer. The nonvolatile memory with the Ge nanocrystals embedded in SiON stack layer exhibits 4 V threshold voltage shift under 10 V write operation. Also, the manufacture technology using the sequent high-temperature oxidation of the a-Si layer acting as the blocking oxide is proposed to enhance the performance of nonvolatile memory devices. (c) 2006 American Institute of Physics.
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.