Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/6737
標題: 非晶矽薄膜電晶體結構變化之探討
Study of Different Device Structures for Amorphous Silicon Thin-Film Transistors
作者: 張祖強
CHIANG, CHANG YSU
關鍵字: 非晶矽;a-Si;薄膜電晶體;TFT
出版社: 電機工程學系
摘要: 
本論文主要在探討各種不同結構之非晶矽薄膜電晶體的寄生效應及在暗態及背光下的漏電現象。我們設計五種後通道蝕刻(Back channel Etched, BCE)結構的薄膜電晶體(Thin-Film Transistor, TFT),分別為S型、U型、L型、A型、T型。其中S型為一般標準型TFT之結構;U型、L型和A型為非對稱式TFT之結構,設計目的為降低TFT的寄生效應;T型為兩顆S型串聯結構,設計目的為降低TFT的漏電流。我們並針對通道長度(channel length, L)、通道寬度(channel width, W)、閘極金屬與汲、源極金屬重疊部分 (overlap)、非晶矽島(a-Si island)等設計變化對這五種結構做分析探討。
TFT在構造上存在許多的寄生電容,其中以Cgs(TFT閘極端與源極端間的寄生電容)對畫面的影響最嚴重,這會造成不論是正極性、負極性的影像訊號驅動,寫入像素電容的電位會與閘極水平脈波變化做同方向的漂移。實驗結果顯示,U型結構的TFT在減少寄生電容Cgs有較佳的表現。
實驗結果也顯示,T型結構的TFT可以降低通道電場的強度,達到抑制漏電流的目的,LCD畫面閃爍及串音現象(crosstalk)則因此可被改善。

In this thesis, parasitic effect and leakage current phenomenon in dark and backlight conditions of amorphous silicon thin-film transistors were studied. Five kinds of back channel etched (BCE) structures, S-type、U-type、L-type、A-type and T-type were designed. In which, S-type is standard TFT structure, and U-type L-type and A-type are asymmetric structures, designed for reducing parasitic capacitances, and T-type is two S-type series connected structure, designed for reducing leakage current. The characters of these five structures were analyzed by changing channel length、channel width、overlap and island pattern.
The research results showed that U-type structure revealed a better performance than other structures in reducing parasitic capacitances between TFT gate terminal and source terminal (Cgs), which lead to pixel dc voltage shift at positive and negative cycles by coupling with gate pulse change.
The result also showed that T-type structure designed in this research could reduce the intensity of electrical field of TFT channel and therefore reduced leakage current. Thus, the flicker and crosstalk phenomena in TFT transistors can be improved.
URI: http://hdl.handle.net/11455/6737
Appears in Collections:電機工程學系所

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