Investigating the origin of Fermi level pinning in Ge Schottky junctions using epitaxially grown ultrathin MgO films
Investigating the origin of Fermi level pinning in Ge Schottky junctions using epitaxially grown ultrathin MgO films
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DOI：
10.1063/1.3357423
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发表时间：
2010-03
影响因子：
4
通讯作者：
Yi Zhou;W. Han;Yong Wang;F. Xiu;J. Zou;R. Kawakami;Kang L. Wang
中科院分区：
文献类型：
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作者：
Yi Zhou;W. Han;Yong Wang;F. Xiu;J. Zou;R. Kawakami;Kang L. Wang
Ge 价带上的费米能级 (FL) 钉扎导致所有金属/n-Ge 接触的肖特基势垒高度较高。这种钉扎效应的起源可归因于金属诱导的间隙态或由Ge表面的固有缺陷（例如悬空键）引起的表面态。报告的结果/解释中的差异主要是由于缺乏对高质量金属/Ge或金属/超薄氧化物/Ge结的明确表征，这些结应该是理想的单晶、原子光滑且没有工艺引起的缺陷或混合。我们报告了高质量金属/MgO/n-Ge 结的肖特基特性，其中超薄 MgO 外延生长在 Ge 上。我们发现脱钉效应对 MgO 厚度的依赖性较弱，这表明由于 Ge 表面的原生缺陷而导致的界面态可能在 FL 钉扎中起主导作用。 © 2010 美国物理研究所
Fermi level (FL) pinning at the Ge valence band results in a high Schottky barrier height for all metal/n-Ge contacts. The origin of this pinning effect has been ascribed to either metal induced gap states or surface states arise from the native defects at the Ge surface, such as dangling bonds. The discrepancy in the reported results/explanations is mainly due to the lack of an explicit characterization of a high quality metal/Ge or metal/ultrathin oxide/Ge junction, which should be ideally single crystalline, atomically smooth and free of process-induced defects or intermixing. We report the Schottky characteristics of high quality metal/MgO/n-Ge junctions with the ultrathin MgO epitaxially grown on Ge. We find the depinning effect displays a weak dependence on the MgO thickness, indicating the interface states due to the native defects on Ge surface are likely to play the dominant role in FL pinning. © 2010 American Institute of Physics