利用電漿輔佐化學氣相沉積法低溫成長石墨烯於銅薄膜

Abstract

本論文探討利用電漿輔佐化學氣相沉積法(PECVD)[1, 2]來優化石墨烯之製程，並於不同之晶格與結構設計來進行生長。PECVD 為一種新式製程，其特點為可在低溫環境下快速生長出石墨烯，相較於傳統之 CVD[3]製程有更進一步之突破。 起先對生長之基板做處理，並以XRD 檢視其晶格結構，本篇使用之銅片晶向為(100)，而銅基板為(111)，再以SEM 及 XPS[4]分析其表面之殘留物質。第一部分為用 PECVD 生長石墨烯於銅片上，並與 CVD 製程之石墨烯做拉曼分析比較，再以XPS、UPS 及 SEM 去對石墨烯進行進一步之分析，判斷其生長之品質與結晶形狀，並比較兩者之優缺。第二部分為進階生長，利用 PECVD 生長石墨烯於銅線及銅基板上，予以應用在不同用途。由於銅基板之晶向與銅片相異，因此製程參數亦有所不同，所以我們分別設計幾種不同結構去調整其變因，並討論分析其生長之結果，而最後用氧化石墨烯塗佈法，成功生長出石墨烯於銅(111)基板上。由於銅(111)晶向和石墨烯之晶格較為匹配，會使得應變(strain)較小，所以石墨烯之品質會更有效提升，因此我們利用 PECVD 生長石墨烯於銅基板，能同時兼顧低溫、快速與品質優良之特點，可更加廣泛應用於業界之中。

In this master thesis, we discuss the way to optimize the growth of graphene by Plasma-Enhanced Chemical Vapor Deposition(PECVD); besides, using different substrates and structure designs. PECVD is a brand new process which carrys out at reduced temperature and within few minutes. Therefore, it could be applied to more academic fields than Chemical Vapor Deposition. Above all, we purity the substrates and examine their lattice by X-Ray Diffraction. Then, we found the lattice of copper foil is (100) and (111) for the copper wafer. Next, SEM and XPS are also used to detect the surface of the substrates. The first part of this thesis is about the growth of graphene on copper foil by PECVD, and compare the graphene quality from Raman spectrum with the process by CVD. In addition, XPS, UPS and SEM are utilized to do deeper analysis. Therefore, we are able to analyze and compare the quality and domain structure of two different process. The second part is advanced growth process. We attempt to grow graphene on copper wire and copper wafer by PECVD process for more application. Due to the different domain structure, the experimental parameters will change significantly. So, we design up-to-date structures and analyze the growth variables. In the end, we create a new process which could successfully grow graphene on copper wafer. Owing to the lattice match of (111)copper and graphene, the strain will shrink and the quality of graphene will become better. As a result, the PECVD process we use hold the advantage of low-temperature, fewer time and higher quality. Thus, we expect that this process could be applied to more fields.