A CMOS-compatible morphotropic phase boundary.

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 ρ_(MPB )and consequently the dielectric constant ϵr of HfO2-ZrO2 thin film was considerably increased. The ρ_(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 ϵr compared to the conventional HfO2-ZrO2 thin film was achieved by controlling the FE-AFE ratio. The fabrication process was performed at low temperature (250 °C) and the device is compatible with silicon technology, so the new design yields a device that has possible applications in near-future electronics.