Premium
Metal Nitride Electrode Stress and Chemistry Effects on Phase and Polarization Response in Ferroelectric Hf 0.5 Zr 0.5 O 2 Thin Films
Author(s) -
Fields Shelby S.,
Smith Sean W.,
Fancher Chris M.,
Henry Michael David,
Wolfley Steve L.,
Sales Maria G.,
Jaszewski Samantha T.,
Rodriguez Mark A.,
Esteves Giovanni,
Davids Paul S.,
McDonnell Stephen J.,
Ihlefeld Jon F.
Publication year - 2021
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202100018
Subject(s) - materials science , ferroelectricity , electrode , polarization (electrochemistry) , crystallite , analytical chemistry (journal) , oxide , orthorhombic crystal system , optoelectronics , dielectric , crystallography , crystal structure , metallurgy , chemistry , chromatography
Ferroelectric phase stability in hafnium oxide is reported to be influenced by factors that include composition, biaxial stress, crystallite size, and oxygen vacancies. In the present work, the ferroelectric performance of atomic layer deposited Hf 0.5 Zr 0.5 O 2 (HZO) prepared between TaN electrodes that are processed under conditions to induce variable biaxial stresses is evaluated. The post‐processing stress states of the HZO films reveal no dependence on the as‐deposited stress of the adjacent TaN electrodes. All HZO films maintain tensile biaxial stress following processing, the magnitude of which is not observed to strongly influence the polarization response. Subsequent composition measurements of stress‐varied TaN electrodes reveal changes in stoichiometry related to the different preparation conditions. HZO films in contact with Ta‐rich TaN electrodes exhibit higher remanent polarizations and increased ferroelectric phase fractions compared to those in contact with N‐rich TaN electrodes. HZO films in contact with Ta‐rich TaN electrodes also have higher oxygen vacancy concentrations, indicating that a chemical interaction between the TaN and HZO layers ultimately impacts the ferroelectric orthorhombic phase stability and polarization performance. The results of this work demonstrate a necessity to carefully consider the role of electrode processing and chemistry on performance of ferroelectric hafnia films.