Local Leakage Current of HfO2Thin Films Characterized by Conducting Atomic Force Microscopy
- 30 April 2003
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 42 (Part 1, No) , 1949-1953
- https://doi.org/10.1143/jjap.42.1949
Abstract
We have characterized the crystallinity and the local leakage current of HfO2 thin films microscopically, using conducting atomic force microscopy and transmission electron microscopy. It is clarified that the leakage path depends strongly upon the HfO2 crystallographic structures. At 700°C deposition, the HfO2 film has mainly polycrystalline columnar grains and stacked polycrystalline grains are scattered on the film. A triplet point at the stacked grains acts as a leakage site, where the thickness for the electron tunneling is effectively reduced. Moreover, in amorphous HfO2 deposited at room temperature, applied voltage shift are observed, indicating that positive charges are present at the HfO2/Si interface. On the other hand, in the HfO2 film deposited at 500°C, in which crystallized grains are scattered in the amorphous structure, no significant conductive region is observed. Therefore, the boundary between crystalline and amorphous regions does not contribute to leakage current.Keywords
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