Premium
Residual stress and electrical properties of Pb(Zr 0.52 ,Ti 0.48 )O 3 thin films RF sputtered directly on Cu foils
Author(s) -
WalenzaSlabe Joel,
Gibbons Brady J.
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15037
Subject(s) - materials science , residual stress , thin film , composite material , thermal expansion , substrate (aquarium) , sputtering , crystallite , analytical chemistry (journal) , metallurgy , nanotechnology , oceanography , chemistry , chromatography , geology
Polycrystalline Pb(Zr 0.52 Ti 0.48 )O 3 ( PZT ) thin films between 250 and 1000 nm thick were deposited on Cu foils via RF magnetron sputtering. Samples were crystallized ex situ between 550°C and 750°C in a low oxygen partial pressure atmosphere, p O 2 , in order to avoid oxidation of the substrate. These were compared to films made on more common Pt/TiO x /SiO 2 /Si substrates also crystallized under low p O 2 conditions. The mismatch of the coefficients of thermal expansion for Cu and PZT caused large compressive residual stresses to develop in the films, whereas films on Pt‐Si experienced more moderate tensile stresses. Stress was measured using the sin 2 ψ method. In addition to mechanical implications, i.e., film cracking and delamination, the effect of residual stress on electrical properties is discussed. Dielectric constants of PZT were lower on Cu than on Pt/TiO x /SiO 2 /Si. This could be due either to a dead layer effect or to the residual stress imposed by the substrate. The remanent polarizations for films on Cu were between 18 and 41 μC/cm 2 , while coercive fields were between 37 and 54kV/cm. Rayleigh analysis was used to describe the role of defects affecting domain wall mobility, as they act as pinning centers and decrease the extrinsic polarization response.