Selective Area Epitaxy of Complex Oxide Heterostructures on Si by Oxide Hard Mask Lift-Off

Abstract

Epitaxial complex oxide heterostructures on Si are an excellent platform for the realization of multifunctional electronic devices to exploit the unique functionalities of the oxides that Si does not possess. It is often necessary to make patterns of epitaxial films on selected areas of Si. Here, a path towards the selective area epitaxial growth of complex oxide heterostructures on Si using a hard mask lift-off technique is reported. A water-soluble oxide (Sr3Al2O6) is used as a lift-off hard mask that can survive the high temperature (similar to 750 degrees C) and oxidizing environments for epitaxial oxide growth and be selectively etched away subsequently using deionized water. It is found that the epitaxial growth of yttria-stabilized zirconia (YSZ) buffer layers on Si is very sensitive to organic residues formed during photolithography. Island patterns of epitaxial (La, Sr)MnO3/CeO2/YSZ heterostructures are successfully fabricated on Si through the use of oxygen plasma treatment to remove residues. A simple and low-cost method to pattern complex oxide single crystals integrated on Si for the realization of multifunctional oxide-integrated electronics is provided in this study.