Fabrication of PbZr_xTi_1-xO₃ Films on Si Structures Using Y₂O₃ Buffer Layers

Abstract

Lead-zirconate-titanate (PbZr x Ti 1- x O 3 :PZT) films were epitaxially grown on Si(111) substrates using Y 2 O 3 buffer layers. Y 2 O 3 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 Y 2 O 3 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 Y 2 O 3 /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.