Thermal stability and interfacial reaction of TiB x films deposited on (1 0 0)Si by dual-electron-beam evaporation

Abstract

The thermal stability of non-stoichiometric TiB x films with various boron-to-titanium ratios and the interfacial reaction in TiB x /(1 0 0)Si systems have been studied. TiB x /(1 0 0)Si samples were prepared by a dual-electron-beam evaporation process, and then annealed at various temperatures. These samples were characterized with X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, sheet resistance and stress measurement. For boron-rich TiB x films with a ratio of B/Ti⩾2.0, an apparent structural change is not observed even after annealing at 1000°C for 1 h. For titanium-rich films with a ratio of B/Ti<2.0, however, there are two competitive solid phase reactions at Si–TiB x interface as a result of annealing: the formation of a titanium silicide layer at the interface and the formation of a stoichiometric TiB 2 layer at the surface, indicating the salicide process. The sheet resistance and the internal stress for TiB x /(1 0 0)Si systems are changed by the solid phase reaction at Si–TiB x interface.