AFM measurement of the grain size in polycrystalline titanium silicides

In titanium silicide. the transition from the high (C49) to the low resisti vity phase (C54) is difficult in small areas. This has been attributed in t he literature to the lack of the nucleation sites for phase transition in s mall areas [1]. The mean grain size is directly related to the nucleation p oint density and its evaluation is important in obtaining data on nucleatio n mechanism of a new crystalline phase. TEM and SEM cross sections show tha t a silicon ridge is formed on the silicon substrate at the silicide grain boundaries, due to the equilibrium between the forces related to the gain-g rain and to the grain-silicon interface energies [2,3]. AFM measurements ha ve been performed on the interface between silicon and silicide after the r emoval of the silicide film. The grain boundaries of the silicide were imag ed using the silicon ridges, allowing us to obtain unambiguous and statisti cally relevant data on the grain size. (C) 2001 Elsevier Science B.V. All r ights reserved.