  Morphotropic phase boundaries (MPBs) show substantial piezoelectric and
dielectric responses, which have practical applications. The predicted
existence of MPB in HfO2-ZrO2 solid solution thin film has provided a new way
to increase the dielectric properties of a silicon-compatible device. Here, we
present a new fabrication design by which the density of MPB and consequently
the dielectric constant of HfO2-ZrO2 thin film was considerably increased. The
density of MPB was controlled by fabrication of a 10-nm [1 nm-Hf0.5Zr0.5O2
(Ferroelectric)/1 nm-ZrO2 (Antiferroelectric)] nanolaminate followed by an
appropriate annealing process. The coexistence of orthorhombic and tetragonal
structures, which are the origins of ferroelectric (FE) and antiferroelectric
(AFE) behaviors, respectively, was structurally confirmed, and a double
hysteresis loop that originates from AFE ordering, with some remnant
polarization that originates from FE ordering, was observed in P-E curve. A
remarkable increase in dielectric constant compared to the conventional
HfO2-ZrO2 thin film was achieved by controlling the FE-AFE ratio. The
fabrication process was performed at low temperature and the device is
compatible with silicon technology, so the new design yields a device that has
possible applications in near-future electronics.
