Electron spectro-microscopic determination of barrier height and spatial distribution of Au and Ag Schottky junctions on boron-doped diamond (001)
Electron spectro-microscopic determination of barrier height and spatial distribution of Au and Ag Schottky junctions on boron-doped diamond (001)
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DOI：
10.7567/jjap.53.05fp03
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发表时间：
2014-05
影响因子：
1.5
通讯作者：
S. Kono;H. Kodama;K. Ichikawa;Taro Yoshikawa;T. Abukawa;A. Sawabe
中科院分区：
文献类型：
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作者：
S. Kono;H. Kodama;K. Ichikawa;Taro Yoshikawa;T. Abukawa;A. Sawabe
采用电子光谱-显微镜方法直接测量了在酸处理过的氧封端金刚石（001）衬底上制备的Au和Ag肖特基结的肖特基势垒高度（SBH）及其空间分布。对于Au-和Ag-肖特基结，形成具有两个厚度范围（对于薄层为3-5 nm，对于厚层为13-100 nm）的金属层。将金属层的Au 4f 7/2或Ag 3d 5/2以及金刚石的C 1 s的主导X射线光电子能谱（XPS）核心水平峰用作SBH的测量。对于厚金属样品，在样品表面的大部分上进行空间分辨XPS测量。发现对于大的（“高势垒”）SBH值，SBH存在0.1eV量级的变化，并且存在SBH相当小的几个地方（“低势垒”结）。对于薄金属样品，观察到SBH的变化较小。厚金属样品的“高势垒”结的平均SBH似乎略大于薄金属样品的平均SBH（0.1 eV量级）。XPS图像的领先金属核心水平调整为“高势垒”和“低势垒”SBH进行了观察。对于厚Ag肖特基样品，所得的Ag 3d 5/2 XPS图像清楚地显示了缺陷肖特基结的位置。建议薄金属样品测定的SBH是测量表面上的平均SBH，厚金属样品测定的SBH是测量的μ m尺寸金属岛内的最高SBH。目前确定的SBH与以前报道的SBH进行了比较，发现合理的协议。光电子显微镜（PEEM）图像观察厚Ag肖特基样品和“低势垒”的岛屿被确定。XPS、XPS成像和PEEM等用于厚金属样品的方法可以应用于任何金刚石肖特基结。
Electron spectro-microscopic methods were applied as direct methods of determining the Schottky barrier heights (SBHs) and their spatial distribution for Au- and Ag-Schottky junctions fabricated on an acid-treated oxygen-terminated diamond (001) substrate. Metal layers were formed with two ranges of thickness (3–5 nm for thin layers and 13–100 nm for thick layers) for both Au- and Ag-Schottky junctions. Leading X-ray photoelectron spectroscopy (XPS) core-level peaks of either Au 4f7/2 or Ag 3d5/2 for the metal layers and C 1s for diamond were used as measures of the SBH. For the thick-metal samples, spatially resolved XPS measurements were performed over most of the sample surface. It was found that there is a variation in SBH on the order of 0.1 eV for the large (“high barrier”) SBH values and that there are several places where the SBHs were rather small (“low barrier” junction). For the thin-metal samples, less variations in SBH were observed. The average SBH of “high barrier” junctions for the thick-metal samples appeared to be slightly (0.1 eV order) larger than that for the thin-metal samples. XPS images of leading metal core levels tuned for the “high barrier” and “low barrier” SBHs were observed. For the thick-Ag Schottky sample, the resulting Ag 3d5/2 XPS images clearly showed the locations of defective Schottly junctions. It is suggested that the SBHs determined for the thin-metal samples are the average SBHs on the measured surface and that the SBHs determined for the thick-metal samples are the highest SBHs within the measured µm-size metal islands. The presently determined SBHs were compared with previously reported SBHs and reasonable agreement was found. Photoemission electron microscopy (PEEM) images were observed for the thick-Ag Schottky sample and the “low barrier” islands were identified. The methodologies of XPS, XPS imaging, and PEEM used for the thick-metal samples can be applied to any Schottky junction on diamond.