Chemistry, microstructure, and electrical properties at interfaces between thin films of titanium and alpha (6H) silicon carbide (0001)

Abstract

Epitaxial thin films (4–1000 Å) of Ti contacts have been deposited via UHV electron beam evaporation at room temperature on monocrystalline, n-type, alpha (6H)-SiC(0001). The interfacial chemistry and microstructure, and the electrical properties, were investigated at room temperature and after annealing at 700 °C up to 60 min. High resolution TEM analyses revealed the formation during annealing of reaction zones consisting of Ti₅Si₃ and TiC. The corresponding electrical properties exhibited considerable stability except after an initial 20 min anneal. Current-voltage (I-V) measurements showed that the Ti contacts were rectifying with low ideality factors (n < 1.09) and typical leakage currents of 5 × 10⁻⁷ A/cm² at −10 V. The Schottky barrier heights calculated from x-ray photoelectron spectroscopy and I-V and V-V measurements were between 0.79 and 0.88 eV for the as-deposited contacts and between 0.86 and 1.04 eV for the annealed contacts.