介電層表面修飾對有機蒸鍍薄膜形貌與其場效電晶體性能影響研究

The effect of surface modification of dielectric layer on the morphology of deposited organic films and performance of field-effect transistors

黃志瑋(Zhi-wei Huang)

指導教授 ： 陶雨台 ； 陳銘洲

國立中央大學/理學院/化學系/碩士(2008年)

摘要

本篇主要包括兩部分，第一部份是利用數種有機三氯矽烷分子((4-alkyl- -oxy phenyltrichlorosilane，n-alkyltrichlorosilane， phenyltrichlorosilane， (hepta- -decafluoro-1,1,2,2,-tetrahyhrodecyl)trichlorosilane)在二氧化矽的表面吸附，形成單一成份或雙成份自組裝單分子層並藉由表面鑑定工具，如橢圓旋光儀和接觸角以及ATR-IR進行表面基本的結構鑑定。第二部分則是將五環素蒸鍍在上述自組裝單分子層上，並且使用AFM，x-ray繞射儀等工具鑑定這些刷磨不同的表面自組裝單分子層對蒸鍍的五環素薄膜的結構或形貌上的影響;並做成有機場效電晶體元件，量測分析元件效能，研究表面修飾薄膜結構與效能之間關聯。
第一部份的研究結果顯示，除了4-alkyloxy phenyltrichlorosilane的長碳鏈對表面法線夾角較大外，其他類型的表面自組裝分子都幾乎垂直於表面(<100)，而且具有碳鏈的單一成份表面自組裝單分子層表面能量較混和單分子層低。第二部份的研究結果顯示，刷磨處理表面自組裝單分子層會使得蒸鍍上的五環素薄膜顆粒變大且較連接。從x-ray也可看出五環素的結晶性變好，而且也使得場效遷移率具有方向性上的差異，場效遷移率也可高達2.46 cm2/Vs。另外混和表面自組裝單分子層(4-alkyloxy phenyltrichlorosilane+phenyltrichlorosilane)製造了較高的粗超度，因而使得五環素的顆粒較小而且較不連接也造成製作出的元件場效遷移率較低。
另外在表面修飾(heptadecafluoro-1,1,2,2,-tetrahyhrodecyl) trichlorosilane，發現OFET元件在Vg=0V時，就有明顯的電流產生(6*10-4A)。

關鍵字

自組裝單分子層 ； 五環素 ； 元件 ； 場效遷移率 ； 表面鑑定 ； 有機場效電晶體 ； 刷磨

並列摘要

The thesis is divided into two parts. In the first part, several organic tri- -chlorosilane derivatives (4-alkyloxyphenyltrichlorosilane, n-alkyltrichlorosilane, phenyltrichlorosilane, heptadecafluoro-1,1,2,2,-tetrahyhrodecyltrichloro silane), were used to form single component or mixed self-assembled monolayers(SAM). Their structures were investigated by ATR-IR, elliposometry and contact angle measurement. The second part is about depositing pentacene thin on the above SAM-modified SiO2 dielectric surface. Effect of SAM modification on the structure and morphology of pentacene films were investigated by AFM and X-ray. Field effect transistors were also fabricated in order to correlate the field effect carrier mobility with the pentacene film structure/surface mofication. In the first part of the study, all single-component SAMs, except that for 4-alkyloxyphenyltrichlorosilane, are forming monolayers with nearly upright packing of the alkyl chains. The 4-alkyloxyphenyltrichlorosilane formed a monolayer with a larger tilt angle of the alkyl chains, presumably due to the packing of phenyl rings requires a larger spacing. Mixed SAMs gave higher surface energy than the single component SAMs, as judged from the contact angle. In the second part of study, it was shown that pentacene film deposited on a SAM that was rubbed first gave larger grains of better crystallinity compare to that deposited on SAM without rubbing treatment. Field effect carrier mobilities also increased with rubbing treatment along the rubbing direction. Pentacene film deposited on mixed SAMs prepared from 4-alkyloxyphenyltrichlorosilane and phenyltrichlorosilane gave smaller grains and poorer mobility, presumably due to the rougher surfaces provided by the mixed monolayer. For pentacene film deposited on silicon oxide surface modified by hepta- -decafluoro-1,1,2,2,-tetrahyhrodecyltrichlorosilane, a substantial current (6*10-4A) was observed at zero gate voltage. The strong negative dipole of CF3 group is suggested to induce hole carriers at the SAM/pentacene interface.

並列關鍵字

SAM ； surface analysis ； transistor ； ATR-IR ； chlorosilane ； contact angle ； device ； ellposometry ； mobility ； field effect ； monolayer

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