Effect of ZrO2 interfacial layer on forming ferroelectric HfxZryOz on Si substrate

Abstract

Ferroelectric HfxZryOz (HZO) with an average polarization switching window of 32 µC/cm2 was demonstrated on a Si substrate with a ZrO2 interfacial layer (IL). It is suggested that the ZrO2 IL below HZO crystallizes in the form of an o-phase prior to HZO crystallization, during rapid thermal annealing, thereby promoting the vertical growth of an o-phase HZO layer. HZO with the ZrO2 IL consists mainly of an o-phase that exhibits an in-plane tensile stress of 2.68 GPa, resulting in superior ferroelectric characteristics. This technology has the potential to expedite the realization of ferroelectric Hf-based dielectrics in advanced memory and logic technology.