TaN interface properties and electric field cycling effects on ferroelectric Si-doped HfO{sub 2} thin films

Journal Article · Tue Apr 07 04:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4916715· OSTI ID:22399388

Lomenzo, Patrick D.; Nishida, Toshikazu ^[1]; Takmeel, Qanit ^[2]; Zhou, Chuanzhen ^[3]; Fancher, Chris M.; Jones, Jacob L. ^[4]; Lambers, Eric; Rudawski, Nicholas G. ^[5]; Moghaddam, Saeed ^[6]

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1. Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida 32611 (United States)
2. Department of Materials Science and Engineering at the University of Florida, Gainesville, Florida 32611 (United States)
3. Analytical Instrumentation Center, College of Engineering at North Carolina State University, Raleigh, North Carolina 27696 (United States)
4. Department of Materials Science and Engineering at North Carolina State University, Raleigh, North Carolina 27696 (United States)
5. Major Analytical Instrumentation Center at the University of Florida, Gainesville, Florida 32611 (United States)
6. Department of Mechanical and Aerospace Engineering at the University of Florida, Gainesville, Florida 32611 (United States)

Ferroelectric HfO{sub 2}-based thin films, which can exhibit ferroelectric properties down to sub-10 nm thicknesses, are a promising candidate for emerging high density memory technologies. As the ferroelectric thickness continues to shrink, the electrode-ferroelectric interface properties play an increasingly important role. We investigate the TaN interface properties on 10 nm thick Si-doped HfO{sub 2} thin films fabricated in a TaN metal-ferroelectric-metal stack which exhibit highly asymmetric ferroelectric characteristics. To understand the asymmetric behavior of the ferroelectric characteristics of the Si-doped HfO{sub 2} thin films, the chemical interface properties of sputtered TaN bottom and top electrodes are probed with x-ray photoelectron spectroscopy. Ta-O bonds at the bottom electrode interface and a significant presence of Hf-N bonds at both electrode interfaces are identified. It is shown that the chemical heterogeneity of the bottom and top electrode interfaces gives rise to an internal electric field, which causes the as-grown ferroelectric domains to preferentially polarize to screen positively charged oxygen vacancies aggregated at the oxidized bottom electrode interface. Electric field cycling is shown to reduce the internal electric field with a concomitant increase in remanent polarization and decrease in relative permittivity. Through an analysis of pulsed transient switching currents, back-switching is observed in Si-doped HfO{sub 2} thin films with pinched hysteresis loops and is shown to be influenced by the internal electric field.

• OSTI ID: 22399388
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 13 Vol. 117; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DOPED MATERIALS
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRODES
FERROELECTRIC MATERIALS
HAFNIUM OXIDES
HYSTERESIS
INTERFACES
OXYGEN
PERMITTIVITY
POLARIZATION
SILICON
TANTALUM NITRIDES
THIN FILMS
VACANCIES
X-RAY PHOTOELECTRON SPECTROSCOPY