紅熒烯薄膜成長與其電晶體電性之臨場表現研究

In-situ growth and electrical characterization studies of rubrene thin film transistors.

林鈺祥(Yu-Hsiang Lin)

指導教授 ： 楊耀文

國立清華大學/理學院/化學系/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00385

摘要

本論文報導運用臨場電性量測技術來研究紅熒烯(rubrene)薄膜電晶體製作過程中，電晶體電性表現與薄膜厚度之變化關係。且利用不同層數之正二十酸鎘(Cadmium arachidate，CdA)薄膜作為基材，來改變基材表層島狀結構的密度，並成長rubrene薄膜於此經過CdA多層膜修飾後之基材。將CdA薄膜與rubrene薄膜分別藉由原子力顯微鏡(Atomic Force Microscope，AFM)、X光繞射(X-ray Diffraction，XRD)、近緣X光吸收細微結構(Near-edge X-ray Absorption Fine Structure，NEXAFS)與光學顯微鏡來分析表面形貌、結構、分子位向與薄膜外觀。
成長rubrene薄膜在具有苯環官能基表面之基材上，可觀察到其rubrene薄膜表面形貌高低差異大，且薄膜為非晶相。再基材經CdA多層膜修飾後，基材表面具豐富結構島狀形貌，於上成長出之rubrene薄膜，其表面形貌較呈平板片狀，且薄膜具高晶相，而且rubrene分子較站立於基材表面。
以4層CdA薄膜成長於具長碳鏈官能基表面作為基材，所製作出之rubrene薄膜電晶體，在臨場量測電晶體特性時，可觀察到電晶體效能隨薄膜厚度而穩定增加，可於rubrene薄膜厚度35 nm時開始量測到場效電晶體特性，此時載子遷移率為4.58 × 10-4 cm2/Vs，而隨薄膜厚度增厚其電晶體載子遷移率也不斷向上提升，當厚度達140 nm時量測到最佳載子遷移率為0.16 cm2/Vs，經熱退火後處理後更提高至0.32 cm2/Vs。而電流開關比約為105，門檻電壓約在-25V。.

關鍵字

紅熒烯 ； 臨場 ； 場效電晶體

並列摘要

We present in-situ transport measurement of rubrene thin film transistors. The rubrene based transistors were fabricated form rubrene grown onto the SiO2/Si substrate modified by Cadmium arachidate (CdA) multi-layers or self-assembled organosilane. The morphology, structure and crystallinity of CdA substrate and rubrene film were characterized by optical microscope, atomic force microscopy (AFM), near-edge absorption fine structure (NEXAFS), x-ray diffraction (XRD).
Rubrene film grown on the substrate modified by aromatic terminated silane, the film shows the irregular pillar-like morphology and amorphous structure. Rrubrene film on multi-layers CdA substrate present more plate-like features and reveal the strong (200)-oriented crystallites on the surface. In addition, the ring plane of the aromatic core of rubrene molecule is stand-up configuration from thin to thick thickness of rubrene films.
The transistor was fabricated form rubrene grown on 4 layers CdA film on SiO2/Si substrate modified by alkyl terminated silane have the characteristic of field effect transistor form 35 nm thickness of rubrene, and the hole mobility is 4.58 × 10-4 cm2/Vs. The hole mobility is increased after increasing the thickness of rubrene film. The highest mobility of 0.16 cm2/Vs was obtained when the rubrene film thickness reached to 140 nm. The final mobility was improved to 0.32 cm2/Vs, after the rubrene film was treated by post thermal annealing.

並列關鍵字

rubrene ； OTFT ； in-situ

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