Title: Ferroelectricity in Si-Doped Hafnia: Probing Challenges in Absence of Screening Charges

Abstract

The ability to develop ferroelectric materials using binary oxides is critical to enable novel low-power, high-density non-volatile memory and fast switching logic. The discovery of ferroelectricity in hafnia-based thin films, has focused the hopes of the community on this class of materials to overcome the existing problems of perovskite-based integrated ferroelectrics. However, both the control of ferroelectricity in doped-HfO2 and the direct characterization at the nanoscale of ferroelectric phenomena, are increasingly difficult to achieve. The main limitations are imposed by the inherent intertwining of ferroelectric and dielectric properties, the role of strain, interfaces and electric field-mediated phase, and polarization changes. In this work, using Si-doped HfO2 as a material system, we performed a correlative study with four scanning probe techniques for the local sensing of intrinsic ferroelectricity on the oxide surface. Putting each technique in perspective, we demonstrated that different origins of spatially resolved contrast can be obtained, thus highlighting possible crosstalk not originated by a genuine ferroelectric response. By leveraging the strength of each method, we showed how intrinsic processes in ultrathin dielectrics, i.e., electronic leakage, existence and generation of energy states, charge trapping (de-trapping) phenomena, and electrochemical effects, can influence the sensed response. We then proceeded to initiatemore » hysteresis loops by means of tip-induced spectroscopic cycling (i.e., “wake-up”), thus observing the onset of oxide degradation processes associated with this step. Finally, direct piezoelectric effects were studied using the high pressure resulting from the probe’s confinement, noticing the absence of a net time-invariant piezo-generated charge. Our results are critical in providing a general framework of interpretation for multiple nanoscale processes impacting ferroelectricity in doped-hafnia and strategies for sensing it.« less

Authors:

Celano, Umberto  ^[1];

• Search DOE PAGES for author "Celano, Umberto"
• Search DOE PAGES for ORCID "0000-0002-2856-3847"

Gomez, Andres ^[2]; Piedimonte, Paola  ^[1];

• Search DOE PAGES for author "Piedimonte, Paola"
• Search DOE PAGES for ORCID "0000-0003-3306-3262"

Neumayer, Sabine M.  ^[3];

• Search DOE PAGES for author "Neumayer, Sabine M."
• Search DOE PAGES for ORCID "0000-0002-8167-1230"

Collins, Liam  ^[3];

• Search DOE PAGES for author "Collins, Liam"
• Search DOE PAGES for ORCID "0000-0003-4946-9195"

Popovici, Mihaela ^[1]; Florent, Karine ^[1]; McMitchell, Sean ^[1]; Favia, Paola ^[1]; Drijbooms, Chris ^[1]; Bender, Hugo ^[1]; Paredis, Kristof ^[1]; di Piazza, Luca ^[1]; Jesse, Stephen  ^[3];

• Search DOE PAGES for author "Jesse, Stephen"
• Search DOE PAGES for ORCID "0000-0002-1168-8483"

Van Houdt, Jan ^[4]; van der Heide, Paul ^[1]

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+ Show Author Affiliations

1. Interuniversity Microelectronics Centre (IMEC), Leuven (Belgium)
2. Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Bellaterra, Spain
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
4. Interuniversity Microelectronics Centre (IMEC), Leuven (Belgium); Katholieke Univ. Leuven, Heverlee (Belgium)

Publication Date:

Tue Aug 11 00:00:00 EDT 2020

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1648869

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Nanomaterials

Additional Journal Information:

Journal Volume: 10; Journal Issue: 8; Journal ID: ISSN 2079-4991

Publisher:

MDPI

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE