CoSi 2 formation in the presence of interfacial silicon oxide

Abstract

Evidence is presented that a reactive capping layer may influence the interfacial reaction in a thin film diffusion system. As a prototype system, we describe the CoSi2 formation in the Ti/Co/SiOx/Si system. We observed that Ti from the capping layer transforms the SiOx diffusion barrier into a CoxTiyOz diffusion membrane, initiating silicide formation. The CoSi2 layer that is formed has a preferential epitaxial orientation. The epitaxial quality is dependent on annealing temperature, Co and Ti thickness. The epitaxial growth may be explained by a combination of Ti-interlayer mediated epitaxy and oxide mediated epitaxy.

Schottky barrier height measurements of Cu/Si(001), Ag/Si(001), and Au/Si(001) interfaces utilizing ballistic electron emission microscopy and ballistic hole emission microscopy

“…3 Other effects must be added to get a more accurate prediction such as image forces, metal induced gap states, and interface defects, which can be sensitive to the fabrication process. 4 Models based upon interface dipoles have been developed that give a better prediction of the barrier height. 5,6 Experimentally, the Schottky barrier height should increase with the work function of the metal and the sum of the barrier heights of n-type and p-type diodes fabricated under similar conditions with the same metal should be equivalent to the band gap of the semiconductor.…”

Calculations of hot electron magnetotransport in a spin-valve transistor at finite temperatures

“…In what follows, the energy is measured from the Fermi level of the metallic base. As mentioned above the Schottky barrier heights are not constant, but have spatial distribution [8], and this affects the energy distribution of injected hot electrons. We then denote the ǫ u and ǫ l as the upper and lower bound of the hot electron energy at zero temperature.…”

“…Then, the electrons injected across the Schottky barrier at the emitter side penetrate the spin-valve base, and the energy of injected hot electrons is influenced by the distribution of Schottky barrier heights [8].…”

“…Since the Schottky barrier heights have roughly 0.2 eV distribution [8], we take 0.8 eV, 0.9 eV, 1 eV for ǫ l , ǫ m , ǫ u in Eqs. (5), (9), and (10) respectively, and the Schottky barrier height at the collector is assumed to be 0.9 eV.…”

“…The function D displays the energy distribution at finite temperatures. Based on the Schottky barrier heights measurement [8], in this calculations we assume that the energy of hot electrons has Gaussian distribution at zero temperature. At finite temperatures, the energy of hot electrons will be redistributed due to thermal energy.…”