Browsing by Author "Lin, Kun-Chih"

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Elimination of photoleakage current in poly-Si TFTs using a metal-shielding structure
(2008)
Lu, Hau-Yan
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Li, Hung-Wei
;
Hu, Chin-Wei
A technology to eliminate the photoleakage current of poly-Si thin-film transistors (TFTs) with top gate structure has been developed. A thin metal film is formed on the glass substrate to be used as a light-shielding layer. The light-shielding layer, buffer layer, and active island are patterned employing the same mask. The leakage current and the variation of subthreshold swing in the proposed devices are suppressed completely under illumination. Due to the parasitic capacitance in the overlap region between the drain side and the metal-shielding layer, a floating voltage coupled from drain bias influences the threshold voltage of the proposed poly-Si TFTs. (c) 2008 The Electrochemical Society.
Temperature coefficient of diode-connected LTPS poly-Si TFTs and its application on the bandgap reference circuit
(2008)
Lu, Ting-Chou
;
Zan, Hsiao-Wen
;
Ker, Ming-Dou
;
Huang, Wei-Ming
;
Lin, Kun-Chih
The temperature coefficient (TC) of n-type diode-connected polycrystalline silicon thin-film transistors (poly-Si TFTs) is investigated. The relationship between TC and the activation energy is observed and explained. It is also found that TC is not sensitive to the deviation of the laser crystallization energy. On the contrary, channel width can effectively modulate TC. By using the diode-connected poly-Si TFTs with different channel widths, a new bandgap reference circuit for precise analog circuit design on glass substrate is proposed and realized. From the experimental results in a LTPS process, the output voltage reference exhibits a very low TC of 195 ppm/degrees C, between 25 degrees C and 125 degrees C.