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-ZrO₂solid 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 MPBρMPBand consequently the dielectric constantϵ_rof HfO₂-ZrO₂thin film was considerably increased. TheρMPBwas controlled by fabrication of a 10 nm [1 nm Hf_0.5Zr_0.5O₂(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 inP-Ecurve. A remarkable increase inϵ_rcompared to the conventional HfO₂-ZrO₂thin 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.