Thermal Aging Effect in Poled Ferroelectric SrBi2(Ta,Nb)2O9 Capacitors

Changes in the electrical properties of poled ferroelectric SrBi 2 (Ta,Nb) 2 O 9 (SBTN) thin-film capacitors caused by high-temperature storage were studied. Current–voltage ( J – V ) characteristics of SBTN capacitors before and after high-temperature storage indicated that the current in SBTN is predominantly carried by electrons and limited by electrode interfaces. The voltage shift in the polarization–voltage ( P – V ) curve caused at high temperatures was ascribed to a bulk effect because there were no definite changes in the interface-limited J – V characteristics before and after high-temperature storage. Assuming the pinning of domains by capturing electrons emitted from traps distributed in the energy gap, we describe the decay in switchable polarization with the power of time. The activation energy for the decay in switchable polarization associated with electron capture was determined to be 0.23 eV based on the temperature dependence of the decay in switchable polarization.