Fabrication of PbZrxTi1-xO3 Films on Si Structures Using Y2O3 Buffer Layers

Abstract

Lead-zirconate-titanate (PbZr _x Ti_1-x O₃:PZT) films were epitaxially grown on Si(111) substrates using Y₂O₃ buffer layers. Y₂O₃ layers were prepared in a molecular beam epitaxy (MBE) apparatus with a single electron beam gun, while PZT films were prepared in a vacuum evaporation chamber with both a crucible and an electron beam gun. It was found from in situ RHEED observation that Y₂O₃ layers grew epitaxially on Si(111) substrates. It was also found from X-ray diffraction analysis that strongly (101)-oriented PZT films grew on the Y₂O₃/Si(111) structures at a substrate temperature of 700°C. Metal-ferroelectric-insulator-semiconductor(MFIS) capacitors were fabricated using this structure, and capacitance-voltage (C–V) curves showed a memory window of about 2.6 V, which is considered to be due to the ferroelectric nature of the PZT film.