臺灣博碩士論文加值系統

近年來，由於液晶顯示器(Liquid Crystal Display, LCD)逐漸朝向大尺寸發展，對於薄膜電晶體(Thin Film Transistor, TFT)的要求也越來越高，而非晶態金屬氧化物半導體擁有高載子遷移率、高均勻度、和低製程溫度等優點使其成為相當熱門的研究題目。其中又以本研究中的非晶態氧化鋅摻銦摻鎵最廣為研究(Amorphous InGaZnO, a-IGZO)，但a-IGZO在沒有保護層PV(Passivation)的情況下易受環境影響造成元件操作偏壓改變，所以PV對於元件是個不可或缺的角色。

在本研究中我們將有上PV的a-IGZO TFT操作於水氣的環境中，且在閘極施加負偏壓並探討它的穩定性。在必須隔絕外界的影響下，元件都有上一層PV，但是我們卻發現水氣下的負偏壓卻會對元件的操作偏壓有相當大的不穩定性。除了在水氣下的負偏壓的穩定性外，我們同時也對有機PV的元件在升溫下的負偏壓實驗做更進一步的探討。在改變了PV材料的情況下確實有改善水氣對元件操作偏壓的影響，但是元件卻在升溫的負偏壓實驗下出現了操作偏壓劣化等情況。而實驗結果顯示，水氣下的負偏壓操作可能會使得水氣吸附於PV而對元件造成操作偏壓的劣化，而有機PV的元件則是由於升溫使PV中的離子擴散至主動層所造成操作偏壓的劣化，在本研究中將探討上述兩種劣化的物理機制。

Recently, more large size LCDs are produced one after another. The performance of Thin Film Transistors needs to be greater than before. Amorphous Metal Oxide TFT has some advantages, for example, high carrier mobility, good uniform, and low process temperature. These advantages make metal oxide TFT become a popular study and the most popular active layer material in metal oxide TFT is InGaZnO TFTS. But unpassivated TFT’s threshold voltage is easy to be effected by environment. So, Passivation is very important for our device.
In this Investigation, we give negative bias on our passivated a-IGZO TFT device in moisture environment. However, we discover that TFT’s Threshold voltage have a shift in positive direction. On the other hand, we also discuss TFT passivated by organic material under high temperature negative bias. The organic passivation truly improves instability in moisture environment, but we observe that TFT’s threshold voltage shift in negative direction under high temperature environment. We think that the degradation under moisture environment is caused by ammonium hydroxide molecule adsorption which on the passivation. And the TFT’s threshold voltage degradation under high temperature environment is created by the hydrogen ion thermal diffusion which in the organic passivation. In our study, we will well discuss these two degradation physical mechanisms.

目錄
誌謝 ii
摘要 v
Abstract vi
目錄 viii
圖次 x
表次 xiii
第一章 序論 1
1.1 研究背景 1
1.2 為何選擇InGaZnO作為主動層的材料? 1
1.3 研究動機 3
第二章 元件結構與基本電性 8
2.1 元件結構 8
2.2 元件基本特性 8
2.2.1 電晶體輸出特性與電壓-電流轉換特性曲線 8
2.2.2 電壓-電容轉換特性 9
第三章 參數萃取與實驗儀器 14
3.1 參數萃取 14
3.2 實驗儀器 16
第四章 保護層為二氧化矽和氮化矽之元件氣氛下的不穩定性 19
4.1 簡介 19
4.2 實驗架構 19
4.3 結果與討論 20
第五章 不同保護層材料在升溫下的電應力可靠度不穩定性 37
5.1 簡介 37
5.2 實驗架構 38
5.3 結果與討論 38
第六章 結論 59
參考文獻 61

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