On the Limits of Scalpel AFM for the 3D Electrical Characterization of Nanomaterials
On the Limits of Scalpel AFM for the 3D Electrical Characterization of Nanomaterials
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论手术刀 AFM 对纳米材料 3D 电学表征的限制
DOI：
10.1002/adfm.201802266
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发表时间：
2018-12-27
影响因子：
19
通讯作者：
Lanza, Mario
中科院分区：
文献类型：
--
作者：
Chen, Shaochuan;Jiang, Lanlan;Lanza, Mario
导电原子力显微镜(CAFM)通过施加温和的接触力，确保良好的电接触，而不会导致额外的高压相关现象(例如，弯曲电、局部热、划痕)，被广泛用于薄电介质的电学表征。最近，CAFM已被用于通过刻蚀薄介质表面来获得其三维电学图像。然而，在刻蚀过程中施加的高接触力/压力对材料电学性能的影响从未被考虑过。通过采集刻蚀区域的横截面电子显微镜图像表明，刻蚀工艺可以改变Al_2O_3薄膜的形貌(产生相变、缺陷的产生和金属渗透)。研究还发现，这项技术在刻蚀过程中严重改变了PSI和Ti02晶片的电学性能，并报道了几个被以前的研究忽略的行为，包括i)在无偏压的情况下观察到大电流，ii)刻蚀速率的不稳定性，以及iii)CAFM尖端的退化。总体而言，这项工作应该有助于更好地理解这项技术的局限性，并在那些它可以真正有用的应用程序中传播它。
Conductive atomic force microscopy (CAFM) has been widely used for electrical characterization of thin dielectrics by applying a gentle contact force that ensures a good electrical contact without inducing additional high-pressure related phenomena (e.g., flexoelectricity, local heat, scratching). Recently, the CAFM has been used to obtain 3D electrical images of thin dielectrics by etching their surface. However, the effect of the high contact forces/pressures applied during the etching on the electrical properties of the materials has never been considered. By collecting cross-sectional transmission electron microscopy images at the etched regions, it is shown here that the etching process can modify the morphology of Al2O3 thin films (producing phase change, generation of defects, and metal penetration). It is also observed that this technique severely modifies the electrical properties of pSi and TiO2 wafers during the etching, and several behaviors ignored in previous studies, including i) observation of high currents in the absence of bias, ii) instabilities of etching rate, and iii) degradation of CAFM tips, are reported. Overall, this work should contribute to understand better the limitations of this technique and disseminate it among those applications in which it can be really useful.