Characterization of local dielectric breakdown in ultrathin SiO2 films using scanning tunneling microscopy and spectroscopy
Characterization of local dielectric breakdown in ultrathin SiO2 films using scanning tunneling microscopy and spectroscopy
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DOI：
10.1063/1.370182
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发表时间：
1999-04
影响因子：
3.2
通讯作者：
Heiji Watanabe;T. Baba;M. Ichikawa
中科院分区：
文献类型：
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作者：
Heiji Watanabe;T. Baba;M. Ichikawa
利用扫描隧道显微镜（STM）和扫描隧道光谱（STS）研究了硅衬底上生长的超薄SiO2薄膜的局部介电击穿。我们发现STM观察可以揭示由热电子注入氧化物产生的单个准击穿点，以及氧化物表面的原子台阶等形貌特征。利用STS研究了电应力前后氧化膜的局部电学性能。我们观察到在超薄氧化膜的准击穿点有泄漏电流通过缺陷层。我们还发现，从泄漏点附近获得的几个隧道光谱显示出明显的负微分电阻。这种现象是由于电子充电效应引起的泄漏路径电导变化所致。此外，我们证实了泄漏点产生的应力极性依赖性，并且氧化物上和SiO2/Si界面上的原子台阶没有影响。
Local dielectric breakdown of ultrathin SiO2 films grown on silicon substrates has been investigated by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). We found that STM observation can reveal individual quasibreakdown spots created by hot-electron injection into the oxide, as well as features of the topography such as atomic steps on the oxide surface. STS was used to study the local electrical properties of the oxide films before and after electrical stressing. We observed a leakage current at the quasibreakdown spots that passed through defect levels in the ultrathin oxide films. We also found that several tunneling spectra obtained from near leakage sites showed clear negative differential resistance. This phenomenon was attributed to the conductance change in the leakage path due to electron charging effects. Moreover, we confirmed the stressing polarity dependence of the leakage-site creation, and that atomic steps on the oxide and at the SiO2/Si interface did no...