Evolution of ferroelectric HfO2 in ultrathin region down to 3 nm

Xuan Tian, Shigehisa Shibayama, Tomonori Nishimura, Takeaki Yajima, Shinji Migita, Akira Toriumi

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96 Citations (Scopus)

Abstract

The ferroelectric properties of ultrathin Y-doped HfO2 films were investigated. Ferroelectricity was demonstrated experimentally in 3 nm-thick Y-doped HfO2 via direct detection of displacement currents during polarization switching. The dependence on the HfO2 thickness within the 30 to 3 nm range revealed that the ferroelectric properties decrease rapidly below a critical thickness. In the ultrathin HfO2 region, methods such as higher Y doping or metal capping annealing were required to further stabilize the ferroelectric phase. These methods could be used to enhance the switchable polarization (Psw) to 35 μC/cm2 in 5 nm- and 10 μC/cm2 in 3 nm-thick Y-doped HfO2. This paper indicates that HfO2 ferroelectricity is scalable even in the ultrathin region.

Original languageEnglish
Article number102902
JournalApplied Physics Letters
Volume112
Issue number10
DOIs
Publication statusPublished - Mar 5 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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