Simultaneous occurrence of multiphases in the interfacial reactions of ultrahigh-vacuum-deposited V and Zr thin films on (111)Si

Abstract

Simultaneous occurrence of multiphases was observed in the interfacial reactions of ultrahigh-vacuum (UHV) -deposited V and Zr thin films on (111) Si by high-resolution transmission electron microscopy in conjunction with fast Fourier transform diffraction analysis and image simulation. For the V/Si system, an amorphous interlayer (a-interlayer), V3Si and V5Si3, were found to form simultaneously in samples annealed at 500 °C for 60 min. For the Zr/Si system, an a-interlayer, Zr5Si3 as well as FeB and CrB types of ZrSi, were observed to form in samples annealed at 440 °C for 40 min. The formation of multiphases appeared to be quite general in the initial stages of interfacial reactions of UHV-deposited refractory metal and rare-earth–metal thin films on silicon. The observation of the prevalence of the formation of multiphases in the initial stages of thin film reactions called for a reexamination of generally accepted ‘‘difference’’ in reaction sequence between bulk and thin-film couples.