Resistivity of Ultrathin (0.6–3.7 nm) IrSi Films on Si(100)

Abstract

Subject classification: 73.30.+y; 73.50.Dn; 73.61.Jc; S1.61 Ultrathin (0.6-3.7 nm) IrSi films are fabricated by electron beam evaporation of iridium metal onto n-type silicon (100) substrates and subsequent silicide formation at 500 C. The sheet resistivity is measured at various temperatures in the range from 15 to 300 K. The polycrystalline c-IrSi films which form for a film thickness in excess of 8 nm show a metal-like behaviour of the resistivity. Ultrathin IrSi films of thickness less than 4 nm show an anomalous resistivity that increases with decreasing temperature. The exponential law observed for the resistivity is found to be consistent with hopping transport in amorphous IrSi predicted by the structure analysis for the thin films.