臺灣博碩士論文加值系統

本論文為應用半導體材料Poly[2,5–bis (3- tetradecyl thiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT-C14)和Poly(methyl methacrylate) (PMMA)之間不互溶的特性，使之在以旋轉塗佈法形成半導體層後，會產生相分離的現象，接著再利用浸泡法以丙酮侵蝕PMMA，使半導體層形成孔洞結構，隨著PBTTT-C14和PMMA混摻比例的不同，孔洞結構的孔徑大小亦會隨之變化，因此利用不同半導體層結構成長於駐極體層Polyimide(PI)的變化，深入探討半導體層與駐極體層界面的缺陷態密度變化，以及對於有機記憶元件的電特性與記憶特性能力之影響。
有機記憶元件製程的部份為應用玻璃基板蒸鍍鋁作為閘極電極，並經由高真空氧電漿蝕刻系統處理後形成高介電氧化鋁作為high-K介電層，成功達到降低元件操作電壓的能力，並且也有助於降低薄膜電晶體的臨界電壓VT，接著由於PI本身有良好的絕緣特性且其分子結構具有側鏈能夠捕捉載子，因此將PI以旋轉塗佈方式使之成膜於閘極電極上作為駐極體層，而廣泛應用於有機薄膜電晶體的高分子材料PBTTT-C14被選擇作為半導體層，最後以銀作為汲極和源極電極，成功完成可於低電壓操作之有機薄膜電晶體元件。
論文所使用之主動層溶液為藉由調控PBTTT-C14與PMMA比例來控制所形成的半導體層孔洞直徑大小，接著再分別以AFM、XRD和吸收光譜分析表面結構變化和結晶性，並且以MIM和MISM結構量測電容對電壓和頻率響應，分析介電層與半導體層的阻抗分析。
本實驗將孔洞結構主動層應用於記憶元件分析，研究介電層與半導體層之間的載子能力，在分析不同結構對記憶元件的影響時，藉由給予閘極瞬間脈衝電壓，量測因載子被束縛後產生元件臨界電壓的偏移，來計算出記憶元件的寫入電壓VP和清除電壓VE並轉換成記憶窗口VMW，探討結構改變對元件記憶效應的變化。從記憶元件量測分析發現當主動層產生孔洞時，是有助於提升元件寫入效應的，並且配合導納分析統整缺陷密度對元件寫入效應影響，發現隨著孔洞直徑增加，孔洞結構對記憶元件在負脈衝電壓時可提升缺陷能態密度，造成載子被束縛量增加，使記憶元件寫入能力增強，但也因缺陷密度增加使清除效應並不明顯，正脈衝電壓並不足以使載子被釋放，清除後臨界電壓偏移量較小。
為了解決清除電壓偏移量較小的現象，實驗提供了兩種有助於釋放在半導體層與駐極體層介面的束縛載子，第一是在施加正脈衝電壓做清除動作時，同時在通道上照射波長為533 nm之綠光雷射，藉由照光可使半導體層激發出電子電洞對，大量產生的電子即可與被束縛的電洞複合，達到清除的效果，量測發現照射綠光雷射清除後，元件臨界電壓可回到原始狀態甚至更往正電壓方向偏移，大幅提升孔洞結構記憶元件之記憶窗口至1.32 V。第二是在半導體層上添加一層少量的N型材料，實驗選用PTCDI-C13H27作為添加材料，分別由滴落塗佈(Drop-casting)和蒸鍍兩種方式成膜並做元件分析，發現若PTCDI-C13H27含量較大時，會造成元件寫入效應明顯下降，然而在添加適量的PTCDI-C13H27時，可在不明顯影響寫入能力的情況下提升元件清除能力，對於蒸鍍PTCDI-C13H27後對不同光強度下做清除動作，可以發現加入PTCDI-C13H27後能夠以較低的光強度達到相同的清除能力，證明添加PTCDI-C13H27可以增加元件注入電子的能力並提升記憶元件的清除能力。

In this thesis, the influences of an embedded porous structure within semiconductor layers for the memory window of organic memory devices were discussed. The relationship between the structural properties of semiconductor layers and the memory effect of devices was analyzed through three parts of experiments.
In the first part, the structural properties of poly [2,5–bis(3-tetradecyl thiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT-C14)-based organic thin-film transistors were investigated. An active layer was composed of a blend of PBTTT-C14 and poly(methyl methacrylate) (PMMA). The porous structure of an active PBTTT-C14 layer was fabricated on the basis of the immiscibility of PBTTT-C14 and PMMA by washing with acetone. The size of the hole structures of the PBTTT-C14 thin film could be controlled by changing the proportion of PBTTT-C14 to PMMA.
In the second part, the electrical characteristics of the PBTTT-C14-based organic memory devices were investigated. The porous structure of the active PBTTT-C14 layer increased the interfacial trap density between dielectric and active layers. As a result, the charge trapping ability of the organic memory devices improved. The trapped charges could be released by exposing the memory devices to green light during the erasing operation. Accordingly, the memory window of PBTTT-C14-based organic memory devices was successfully improved by this porous structure.
In the third part, an N-type N,Nʹ-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13) film was deposited onto a porous PBTTT-C14 layer to heterojunction-based memory devices. The N-type film provided minority carriers (electrons) for the P-type PBTTT-C14-based memory device during the erasing process. Consequently, the hole erasing ability of organic memory devices improved. An increase in the minority resulted in a decrease in light intensity during the erasing process. In conclusion, the porous structure was effectively utilized to enlarge the memory window of low-voltage-driven organic memory devices.

中文摘要 I
Extended Abstract IV
誌謝 X
目錄 IV
表目錄 XV
圖目錄 XVI
第一章 緒論 1
1.1 有機薄膜電晶體介紹 1
1.2 有機記憶元件介紹 1
1.3 研究動機 3
第二章 有機薄膜電晶體與記憶元件操作原理 5
2.1 薄膜電晶體架構 5
2.2 有機薄膜電晶體原理 6
2.3 臨界電壓 7
2.4 記憶元件操作原理 8
2.4.1 記憶元件寫入電壓VP與清除VE 8
2.5 導納分析 9
第三章 實驗方法與儀器介紹 13
3.1 實驗材料 13
3.1.1 玻璃 13
3.1.2 金屬電極 13
3.1.3 聚醯亞胺 14
3.1.4 PBTTT -C14 14
3.1.5 聚甲基丙烯酸甲酯 14
3.1.6 PTCDI-C13H27 15
3.1.7 有機溶劑 15
3.2 有機薄膜電晶體元件製程 16
3.2.1 基板切割與清潔 16
3.2.2 閘極蒸鍍 16
3.2.3氧化絕緣層 16
3.2.4 有機高分子駐極體層 17
3.2.5 半導體薄膜層 17
3.2.6 汲極、源極電極 18
3.3 實驗儀器 18
3.3.1 超音波震盪器 18
3.3.2 物理氣相沉積儀 18
3.3.3 高真空電漿蝕刻系統 19
3.3.4 旋轉塗佈機 19
3.4 分析儀器 20
3.4.1 半導體參數分析儀 20
3.4.2 電容分析儀 20
3.4.3 吸收光譜儀 20
3.4.4 原子力顯微鏡 21
3.4.5 X-ray繞射分析儀 21
第四章 實驗結果與討論 22
4.1 前言 22
4.2 半導體層薄膜分析 23
4.2.1 AFM表面形貌 23
4.2.2 XRD分析 24
4.2.3 吸收光譜 24
4.3 有機薄膜電晶體電特性分析 25
4.3.1 轉換特性曲線 25
4.3.2 元件記憶效應 26
4.3.3 導納分析 27
4.3.4 光輔助清除對元件記憶效應分析 29
4.4 PTCDI-C13H27對記憶元件電特性影響 29
4.4.1 滴落塗佈(Drop-casting)成膜PTCDI-C13H27對孔洞結構表面影響 30
4.4.2 滴落塗佈成膜PTCDI-C13H27對元件記憶效應影響 31
4.4.3 蒸鍍PTCDI-C13H27薄膜對記憶元件電特性影響 33
第五章 結論 55
5.1 實驗結論 55
5.2 未來工作 58
參考文獻 59

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