Reactions between Si and thin films of rare‐earth metals (Gd, Dy, Ho, Er, plus Y and La) in the temperature range of 275–900 °C have been studied by using x‐ray diffraction and ion backscattering spectrometry. The disilicides of these metals are apparently the first phase to form, forming rapidly within a narrow temperature range (325–400 °C), and are stable up to 900 °C. The growth does not follow a layered growth mode.