Reliability improvement of ferroelectric Hf0.5Zr0.5O2 thin films by Lanthanum doping for FeRAM applications

Abstract

A century ago ferroelectricity was discovered by J. Valasek[1] which can be used in non-volatile memory applications based on two energetically stable distinct electric polarization states. The conventional perovskite based ferroelectric materials suffer from CMOS incompatibility and scalability issues, hence cannot be used in state of the art scaled CMOS technologies. In 2011, ferroelectricity was reported in CMOS compatible scaled doped HfO2 films [2-3], which can solve the integration issues of perovskites based ferroelectrics. Among the HfO2 based ferroelectric materials, the mixed oxide of HfO2 and ZrO2 (Hf0.5Zr0.5O2) exhibits good ferroelectric properties with a wide process window and CMOS back-end compatible thermal budget.