Atomic layer deposition of Al2O3 on NF3-pre-treated graphene
Atomic layer deposition of Al2O3 on NF3-pre-treated graphene
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DOI：
10.1117/12.2181242
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发表时间：
2015-06
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影响因子：
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通讯作者：
Marcel Junige;Tim Oddoy;R. Yakimova;V. Darakchieva;C. Wenger;G. Lupina;J. Kitzmann;M. Albert;J. Bartha
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文献类型：
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作者：
Marcel Junige;Tim Oddoy;R. Yakimova;V. Darakchieva;C. Wenger;G. Lupina;J. Kitzmann;M. Albert;J. Bartha
石墨烯已经被考虑用于各种应用，包括新型纳米电子器件概念。然而，由于石墨烯缺乏悬挂键，在石墨烯顶部沉积超薄高k层仍然具有挑战性。已经观察到大的岛和漏膜的形成，导致从一个非常延迟的生长开始。为了解决这个问题，我们在Al 2 O3的原子层沉积（ALD）之前测试了用NF 3代替XeF 2对CVD石墨烯以及外延石墨烯单层的预处理。所有实验均在真空中进行; i. e.在施加30个（TMA-H2O）ALD循环之前，立即将原始石墨烯样品在同一反应器中暴露于NF 3，并在高真空条件下将样品在ALD反应器和表面分析单元之间转移。ALD生长起始通过原位实时光谱椭圆偏振仪（irtSE）以高于1Hz的采样率观察。通过真空中X射线光电子能谱（XPS）交叉检查通过施加的30个ALD循环沉积的Al 2 O3材料的总量。通过原子力显微镜（AFM）测定Al 2 O3的形貌。在涂覆程序之前和之后，分别通过真空XPS和拉曼光谱检查石墨烯的存在及其缺陷状态。
Graphene has been considered for a variety of applications including novel nanoelectronic device concepts. However, the deposition of ultra-thin high-k dielectrics on top of graphene has still been challenging due to graphene's lack of dangling bonds. The formation of large islands and leaky films has been observed resulting from a much delayed growth initiation. In order to address this issue, we tested a pre-treatment with NF3 instead of XeF2 on CVD graphene as well as epitaxial graphene monolayers prior to the Atomic Layer Deposition (ALD) of Al2O3. All experiments were conducted in vacuo; i. e. the pristine graphene samples were exposed to NF3 in the same reactor immediately before applying 30 (TMA-H2O) ALD cycles and the samples were transferred between the ALD reactor and a surface analysis unit under high vacuum conditions. The ALD growth initiation was observed by in-situ real-time Spectroscopic Ellipsometry (irtSE) with a sampling rate above 1 Hz. The total amount of Al2O3 material deposited by the applied 30 ALD cycles was cross-checked by in-vacuo X-ray Photoelectron Spectroscopy (XPS). The Al2O3 morphology was determined by Atomic Force Microscopy (AFM). The presence of graphene and its defect status was examined by in-vacuo XPS and Raman Spectroscopy before and after the coating procedure, respectively.