Epitaxial La-doped SrTiO3 on silicon: A conductive template for epitaxial ferroelectrics on silicon

Use of an epitaxial conducting template has enabled the integration of epitaxial ferroelectric perovskites on silicon. The conducting template layer, LaxSr12xTiO3 ~LSTO!, deposited onto ~001! silicon wafers by molecular-beam epitaxy is then used to seed $001%-oriented epitaxial perovskite layers. We illustrate the viability of this approach using PbZr0.4Ti0.6O3 ~PZT! as the ferroelectric layer contacted with conducting perovskite La0.5Sr0.5CoO3 ~LSCO! electrodes. An important innovation that further facilitates this approach is the use of a low-temperature ~450 °C! sol–gel process to crystallize the entire ferroelectric stack. Both transmission electron microscopy and x-ray diffraction analysis indicate the LSCO/PZT/LSCO/LSTO/Si heterostructures are epitaxial. The electrical response of ferroelectric capacitors ~for pulse widths down to 1 ms! measured via the underlying silicon substrate is identical to measurements made using conventional capacitive coupling method, indicating the viability of this approach. © 2002 American Institute of Physics. @DOI: 10.1063/1.1484552#