La2O3, and Al2O3, were evaluated in the form of interfacial oxide layers as potential modifications to achieve increased electric field cycling endurance and polarization retention in comparison to the parent stand-alone Hf0.5Zr0.5O2 capacitor structure. Although it was possible to modify the ferroelectric and conductive behavior of the capacitor, the addition of an interfacial oxide layer also introduced parasitic effects which hampered the improvements. This, nevertheless, was material dependent, with La2O3 outperforming Al2O3.