Tackling Polar Response in Oxygen Deficient KTaO3 Thin Films

Abstract

Oxygen deficient KTaO3 thin films were grown by RF magnetron sputtering on Si/SiO2/Ti/Pt substrates. Room temperature X-ray diffraction shows that they are under a compressive strain of 2.3%. Leakage current results reveal the presence of a conductive mechanism, following Poole-Frenkel formalism. The existence of a polar response below T-pol approximate to 367 degrees C was ascertained by dielectric, polarization, and depolarization current measurements. A Cole-Cole dipolar relaxation was evidenced which is associated with oxygen vacancies induced dipoles. After annealing the films in an oxygen atmosphere above T-pol, the aforementioned polar response is suppressed, due to significant oxygen vacancies reduction.