A CMOS-compatible morphotropic phase boundary

Abstract Morphotropic phase boundaries (MPBs) show substantial piezoelectric and dielectric responses, which have practical applications. The predicted existence of MPB in HfO 2 –ZrO 2 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 M P B and consequently the dielectric constant ϵ r of HfO 2 –ZrO 2 thin film was considerably increased. The ρ M P B was controlled by fabrication of a 10 nm 1 nm Hf 0.5 Zr 0.5 O 2 (ferroelectric)/1 nm ZrO 2 (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 ϵ r compared to the conventional HfO 2 –ZrO 2 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.