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  • 學位論文

電荷儲存點對於有機場效電晶體型記憶體元件特性之影響

Effects of Charge Storage Sites on the Characteristics of Organic Field Effect Transistor Type Memory Devices

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摘要


有機場效電晶體型記憶體由於具有可饒性質、可利用溶液製程製備、製成花費低、非破壞性之讀取以及具有集成電路的結構兼容性,因此近年來在非揮發型記憶體中相當受到矚目。根據電荷儲存機制的不同,場效電晶體記憶體可分成浮動閘極、高分子介電質以及鐵電物質等三種記憶體。其中,浮動閘極記憶體由於可藉由改變奈米粒子或奈米晶體的種類來輕易地控制或調整電荷滯留點的大小、密度以及功函數,因此在新穎的元件應用上具有一定的發展潛力。在此碩士論文中,我們分別製備金屬/半導體奈米複合物、小分子以及無機物等三種不同類型的電荷儲存點為基礎之場效電晶體記憶體來探討對於記憶體元件特性之影響。 1. 以聚9,9二辛基芴-二噻吩共聚高分子與金奈米粒子/氧化鋅奈米柱複合物組成之混摻層為基礎之有機揮發性場效電晶體記憶體 (第二章) 我們以主動層(聚9,9二辛基芴-二噻吩共聚高分子)與電荷滯留點(金/氧化鋅奈米複合物) 之混摻層為基礎來製備場效電晶體記憶體。藉由改變不同濃度之金/氧化鋅奈米複合物來研究它對於元件記憶體特性之影響。結果顯示,金/氧化鋅奈米複合物於記憶體特性中主要支配電子滯留之能力。此外,為了瞭解金奈米粒子與氧化鋅奈米柱在此複合物之貢獻度,我們在同樣條件下以金奈米粒子與氧化鋅奈米柱為基礎製備場效電晶體記憶體。藉此,了解到電子滯留之能力主要來自於金奈米粒子,而氧化鋅奈米柱對於記憶體特性為次要之影響,主要扮演傳遞者的角色,幫助電子更容易傳遞到金奈米粒子儲存。因此以金/氧化鋅奈米複合物(67.67 V)相較於金奈米粒子(42.84 V)製備成的記憶體,其記憶體操作範圍較大(約1.5倍)。於一萬秒訊號維持測試中,還可維持約102之高低訊號比。於寫入-讀取-擦拭-讀取(WRER)測試中,此元件可承受100次以上的反覆操作並維持約102之高低訊號比。因此,以金/氧化鋅奈米複合物為基礎之元件在場效電晶體記憶體的應用上有一定之潛力。 2. 以聚甲基丙烯酸甲酯與小分子組成之混摻層為基礎之有機非揮發性場效電晶體記憶體 (第三章) 我們以主動層五環素以及由聚甲基丙烯酸甲酯與小分子組成之電荷滯留層為基礎來製備場效電晶體記憶體。其中分別以7,7,8,8-四氰基對苯二醌二甲烷與2,3,5,6-四氟-7,7',8,8'-四氰二甲基對苯醌兩種小分子當作電荷滯留點,並且比較它們對於電性影響的差異。以7,7,8,8-四氰基對苯二醌二甲烷為基礎之元件具有顯著的記憶體性質,包含大的記憶體操作空間(52.5 V)、於寫入-讀取-擦拭-讀取(WRER)測試中可被穩定操作100次以上並維持約103之高低訊號比、一萬秒訊號維持測試中,還可維持約102之高低訊號比。而以2,3,5,6-四氟-7,7',8,8'-四氰二甲基對苯醌之元件並不具有顯著的記憶體性質,例如:小的記憶體操作空間以及無法明顯地判斷高低訊號比。造成這兩種小分子為基礎之記憶體電性上的差別,可能原因來自於能階上的差異,使得兩種小分子儲存電荷能力的不同。無論如何,以7,7,8,8-四氰基對苯二醌二甲烷為基礎之元件在場效電晶體型記憶體的應用上有一定之潛力。 3. 以聚甲基丙烯酸與氧化鋅組成之混摻層為基礎之有機非揮發性場效電晶體記憶體 (第四章) 我們以主動層五環素以及由聚甲基丙烯酸與氧化鋅組成之電荷滯留層為基礎來製備場效電晶體記憶體。其中以氧化鋅當作電荷儲存點,包含氧化鋅奈米粒子與氧化鋅奈米柱,並比較他們電性上的差異。而氧化鋅奈米柱是由氧化鋅奈米粒子進一步製備出來的。電性上比較,以氧化鋅奈米柱(60.26 V)為基礎之元件能夠得到比氧化鋅奈米粒子(49.05 V)為基礎之元件較大的記憶體操作空間。於一萬秒的訊號維持測試中,他們各自可維持102與103之高低訊號比。此外,於寫入-讀取-擦拭-讀取(WRER)測試中,他們皆可被穩定操作100次以上並維持約103之高低訊號比。造成這兩種記憶體電性上的差別,可能原因來自於氧化鋅奈米粒子與奈米柱在尺寸以及構型上的不同。總之,以氧化鋅為基礎之元件在場效電晶體型記憶體的應用上有一定之潛力。

並列摘要


Organic filed-effect transistors (OFETs) type memories are especially attractive recently in organic nonvolatile memory devices, due to their advantages of low cost, flexibility, solution processes, non-destructive read-out and architectural compatibility with integrated circuits composed of OFETs. According to the charge storage mechanisms, OFET memory devices can be classified into three types: (i) floating gate memory, (ii) polymer electrets memory, (iii) ferroelectric memory. Among the OFET memories, the floating-gate type memories can potentially be applied to novel device application areas, owing to the charge storage sites can be easily controlled and tuned by varying the size, density and work functions of nanoparticle or nanocrystal species. In this thesis, we explored the OFET memory with three types of charge trapping sites of (1) metal and semiconductor nanocomposites and (2) small molecules, (3) inorganic materials to realize the influence on the characteristics of the memory devices. Organic Nonvolatile Field-Effect Transistor Memory Devices Based on Hybrid Film Composed of Poly(9,9-dioctyl-fluorene-co-bithiophene) and Gold Nanoparticle/Zinc Oxide Nanorod Composites (Chapter 2): We have prepared the OFET memory based on the hybrid layer which was composed of the active layer, poly (9, 9-dioctylfluorene-co-bithiophene) (F8T2), and the charge trapping sites (gold/zinc oxide nanocomposites, Au/ZnO NCs). The effects of Au/ZnO NCs on the electrical memory characteristics of devices were investigated by varied the additions of Au/ZnO NCs. The Au/ZnO NCs primarily dominated the electrons trapping effect in memory behaviors. Moreover, to evaluate the contributions of gold nanoparticles (Au NPs) and zinc oxide nanorods (ZnO NRs) in the Au/ZnO NCs, we also fabricated the devices with gold Au NPs and ZnO NRs, respectively. In Au/ZnO NCs, the ability of electron trapping was caused from Au NPs, while ZnO NRs preferred to be a role of transmitter which helped electron easily transferred and showed a minor effect on memory property. Thus, the memory window of Au/ZnO NCs devices (67.67 V) was larger than that of Au NPs devices (42.84 V) with one and half times. The retention time test of the devices with F8T2/(Au/ZnO NCs) hybrid layer showed the on/off current ratio (Ion/Ioff) of around 102 at least 104 s and the devices could be operated over than 100 cycles with Ion/Ioff of 102 in write-read-erase-read (WRER) cycles test. This device based on Au/ZnO NCs could have potential for the applications of OFET memories. Organic Nonvolatile Field-Effect Transistor Memory Devices Based on Blending Layer Consisted of Poly (methyl methacrylate) and Small Molecules (Chapter 3): We have demonstrated OFET memory devices based on pentacene with the charge trapping layer consisted of poly (methyl methacrylate) (PMMA) and small molecules. The small molecules served as the charge storage sites (floating gate), including tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) for comparison of the electrical characteristics between them. The devices had significant memory characteristics based on TCNQ, including large memory window of 52.5 V, could be operated over than 100 cycles with high on/off ratio of 103 in WRER cycles test, the retention time test could maintain on/off ratio of 102 at least 104 s. There were no significant memory characteristics of the devices based on F4TCNQ, such as small memory window and the on/off states couldn’t be clearly distinguished. The possible reason for the difference between the two species of small molecules was the energy level. However, the devices based on TCNQ could be potentially applied to OFET memories. Organic Nonvolatile Field-Effect Transistor Memory Devices Based on Blending Layer Consisted of Poly (methacrylic acid) and Zinc Oxide (Chapter 4): We have fabricated OFET memory devices based on pentacene with the charge trapping layer composed of poly (methacrylic acid) (PMAA) and zinc oxide (ZnO). The ZnO was used to as the charge storage sites, including ZnO nanoparticles (NPs) and nanorods (NRs) for comparison of the electrical properties between them. The ZnO NRs were synthesized from ZnO NPs. The devices with ZnO NRs showed larger memory windows (60.26 V) than that with ZnO NPs (49.05 V). In retention time test, the devices showed current on/off ratio of around 103 and 102 for ZnO NPs and NRs at least 104 s, respectively. In WRER cycles test, the devices based on ZnO could be operated over than 100 cycles with on/off ratio of around 103. The possible reason for the difference between ZnO NPs and NRs were the size and configuration of them. The devices based on ZnO showed the potential applications for OFET memories.

並列關鍵字

nanoparticle nanorod small molecule floating gate memory transistor

參考文獻


(84) Lee, W.-Y.; Cheng, K.-F.; Wang, T.-F.; Chen, W.-C.; Tsai, F.-Y. Thin Solid Films 2010, 518, 2119.
(92) Chiu, Y.-C.; Liu, C.-L.; Lee, W.-Y.; Chen, Y.; Kakuchi, T.; Chen, W.-C. NPG Asia Mater. 2013, 5, e35.
(71) Han, S. T.; Zhou, Y.; Wang, C.; He, L.; Zhang, W.; Roy, V. A. Adv. Mater. 2013, 25, 872.
(116) Ju, S.; Li, J.; Liu, J.; Chen, P.-C.; Ha, Y.-g.; Ishikawa, F.; Chang, H.; Zhou, C.; Facchetti, A.; Janes, D. B.; Marks, T. J. Nano Lett. 2007, 8, 997.
(73) Liu, C.-L.; Kurosawa, T.; Yu, A.-D.; Higashihara, T.; Ueda, M.; Chen, W.-C. J. Phys. Chem. C 2011, 115, 5930.

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