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

Abstract

We have successfully depositedmultilayer Si/TiN/Si(100) epitaxialheterostructures 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 epitaxialgrowth in systems with large lattice mismatch. Modeling of the domain matching epitaxialgrowth in the high lattice mismatch (100)Si/(100)TiN/(100)Si system and possible device implications are discussed.