CAREER: Perovskite Buffer Layers for Compound Semiconductor-Silicon Heteroepitaxy

University Of Delaware, Newark DE

Investigators

Abstract

This research program will investigate the use of perovskite buffer layers for compound semiconductor-on-silicon heteroepitaxy. Perovskite buffer layers offer potential solutions to lattice mismatch challenges in heteroepitaxy. During the growth of perovskite films on silicon, oxygen diffuses to the interface and creates an amorphous SiOx region that separates the perovskite epitaxial layer from the silicon substrate. The perovskite layer can then act as a template for subsequent epitaxial layers such as compound semiconductors. The research program will determine if the amorphous SiOx interface sufficiently relieves the lattice mismatch strain generated in the epitaxial layers and also traps dislocation defects at the interface. Perovskite "buffer" layers may therefore enable low defect density heteroepitaxy on silicon substrates. The technology has enormous potential to create new designs that integrate optically active devices with the power of silicon CMOS logic. The research will provide new scientific understanding of metalorganic chemical vapor deposition and atomic layer deposition methods to be used for the growth of strontium nucleation layers and SrTiO3 buffer layers. Experimental investigations will develop the chemistry and reaction engineering fundamentals necessary for successful growth of high quality epitaxial perovskite layers on silicon. The perovskite buffer layers will be used as substrates for III-V/silicon heteroepitaxy. Investigations will analyze the gas phase and surface reaction chemistry of the strontium and titanium organometallic precursors. Research efforts will optimize the materials quality through reactor design and operation. Special challenges include controlling precursor transport to the reaction zone, avoiding premature adduct formation and/or decomposition, and achieving high quality monocrystalline, epitaxial layers.