Oriented ferroelectric La-Sr-Co-O/Pb-La-Zr-Ti-O/La-Sr-Co-O heterostructures on [001] Pt/SiO2 Si substrates using a bismuth titanate template layer

Abstract

We demonstrate the growth of c‐axis oriented La‐Sr‐Co‐O/Pb‐La‐Zr‐Ti‐O/La‐Sr‐Co‐O ferroelectric capacitor heterostructures on a highly [001] oriented Pt film which was grown on a thermally oxidized Si (SiO₂/Si) substrate. The [001] growth orientation in the Pt film is induced by depositing it on a thin c‐axis oriented bismuth titanate template layer which is previously grown on the SiO₂/Si substrate. The test capacitors show saturation and remnant polarization values comparable with that obtained on single‐crystal LaAlO₃ substrates. The use of a Pt layer reduces the sheet resistance of the bottom electrode stack by at least 3–5 times. Since the Pt layer is strongly [001] oriented, it favors the growth of [001] La‐Sr‐Co‐O (LSCO) and lead zirconate titanate layers. The use of the LSCO top and bottom electrodes in contact with the ferroelectric thin film provides the resistance to bipolar fatigue, consistent with our earlier results.