最近,薄膜電晶體液晶顯示器已逐漸取代傳統陰極射線管的螢幕,未來為了增加顯示螢幕在可攜式電子用品的應用,顯示器的主動陣列勢必製造在可彎曲甚至於可捲的基材上。利用如此的基材取代玻璃來製造顯示器,有輕薄和不易破裂的好處。然而,假如我們選擇塑膠材質做為基板,就會面臨製程溫度的限制,所以,在本論文中,我們試著利用兩種技術在塑膠材質的基板製作薄膜電晶體。 首先,我們嘗試於低溫(150℃)直接在玻璃上製作元件,並且從三個部份去改善低溫薄膜電晶體的特性,分別是：閘極介電層材質的最佳化、半導體層和介電層介面的改善,以及半導體層和 n+ 非晶矽層的接觸電阻。然後,我們分別評估了Al2O3和TiO2做為塑膠基材上阻絕水氣用之薄膜(hot coating layer)的可行性, 並且選擇PES做為我們的塑膠基板。此外,為了評估TFT在彎曲塑膠基板上電性的表現,我們也嘗試用轉印法把一般製程溫度下製造的電晶體轉移至塑膠基材上。最後根據在150℃所做的測試,我們可以在塑膠基板上製造出,電性表現符合液晶顯示器所需的開關元件特性。

Abstract Recently, a-Si:H TFT based liquid-crystal display has encroached on the territory of the cathode ray tubes. There is a tendency to fabricate the active matrix LCD on the plastic or flexible substrates. Instead of glass, flexible substrates will make the application of TFT-LCD extensive due to the several advantages: i.e. ultra-slim, light-weight and unbreakable, etc. Nevertheless, the limitation of process temperature for the low-melting substrates is an important issue. In this thesis, the feasibility of a-Si TFT devices fabricated on flexible substrates by using two different technologies have been evaluated. First, a-Si TFT devices were fabricated on glass at 150℃successfully and the characteristics of films deposited at lowtemperature have been studied sequentially. For improving the adhesion between organic and inorganic layers and protecting substrate against water or gas during processes, several hot coating layers were investigated. With hot coating layer be introduced, glass was substituted by plastic substrates. We chose PES as the flexible substrate from several candidates due to better optical transmittance and good thermal stability below 200℃. After direct fabrication on flexible substrate, the stability of electronic characteristics were been investigated with bending examination.
In addition, TFT devices were successfully separated from glass and transferred to flexible substrates such as PES or metal foil. Using this technology, temperature limitation has been circumvented and TFT devices still exhibit good electronic characteristic. Furthermore, the bending measurements have been also applied to devices.

Abstract (Chinese) ……………………..…………………………. Abstract (English) ……………
Acknowledgment (Chinese) ……………………………………Content …………….……………………………………………...…Table Captions …………………………………………………………ix Figure Captions …………………………..…………………………...xi Chapter.1 Introduction 1.1 Introduction ……………………………..…………………1 1.2 Motivation ………………………………….…..………….3 1.3 Organization of This Thesis ……………………..………4 Chapter.2 Flexible substrates and the separation/transfer method 2.1 Introduction ………………………………....................... 2.2 Flexible substrates ………………...……………….........7 2.2.1 Metal foil ………………………...…………….........7 2.2.2 Thin glass ………………..………………………….8 2.2.3 Plastic ……………………………………………...10 2.3 The requirement of the plastic substrates …………...11 and the hot coating layers 2.3.1 The requirement of plastic substrates ………...11 2.3.2 The thermal stability of plastic substrates …….12 2.3.3 The reason why we use hot coating layers …..132.4 The separation and transfer method .…………………14 2.4.1 Experiment Process …………………………….14 2.4.2 Result and Discussion …………………………..15 2.5 Conclusion ………………………………………………16 Chapter.3 The low temperature fabrication on glass 3.1 Introduction.…………………...…………………………17 3.2 Low temperature deposition….………………………...19 3.2.1 The mechanism of the PECVD…………………..19 3.2.2 Amorphous silicon…………………………………20 3.3 Experiment Process….………………………………….22 3.3.1 The gate dielectric………………………. ………22 3.3.2 The fabrication of amorphous silicon .………....24 thin film transistor 3.4 Result and Discussion…………………………………..25 3.4.1 Gate dielectric optimization……………………..25 3.4.2 The characteristics of amorphous ……………..26 thin film transistor 3.5 Conclusion………………………………………………..29 Chapter.4 The direct fabrication on PES 4.1 Introduction.……………………………………….……. 30 4.2 Experimental Procedure……………………….…….....314.2.1 Contact resistance extraction…………………...31 4.2.2 DC stress…………………………………………..35 4.2.3 Direct fabrication on PES………………………...35 4.3 Result and Discussion………………………………….37 4.3.1 Contact resistance………………………………..37 4.3.2 DC stress…………………………………………..38 4.3.3 Direct fabrication on PES………………………...39 4.4 Conclusion……………………………………………….41 Chapter 5 Conclusions and Suggestion for Future Work…………43 5.1 Conclusions……………………………………………...43 5.2 Suggestions for Future Work…………………………..44 Reference……………………………………………………………..46

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