Pulsed laser deposition of epitaxial Si/TiN/Si(100) heterostructures

Abstract

We have successfully deposited multilayer Si/TiN/Si(100) epitaxial heterostructures using pulsed laser deposition technique. This silicon-on-conductor device configuration has potential applications in three-dimensional integrated circuits and radiation hardened devices. The Si and TiN films were deposited by pulsed laser (KrF: λ=248 nm, τ =25 ns) physical vapor deposition technique at a substrate temperature of 600 °C in a chamber maintained at a vacuum of ∼10−7 Torr. The epitaxial nature of the films was characterized using x-ray diffraction, Rutherford backscattering, and high resolution transmission electron microscopy techniques. The two interfaces (100)TiN/Si(100)substrate and (100)Si/(100)TiN layers were quite sharp without any indication of interfacial reaction between them. The epitaxial relationship was found to be 〈100〉Si∥〈100〉TiN∥〈100〉Si. In the plane, four unit cells of TiN matched with three unit cells of silicon with less than 4.0% misfit. This domain matching epitaxy provides a mechanism of epitaxial growth in systems with large lattice mismatch. Modeling of the domain matching epitaxial growth in the high lattice mismatch (100)Si/(100)TiN/(100)Si system and possible device implications are discussed.