Formations of germanides in thin films of the Ti-Ge system were investigated by XRD after furnace annealing for 1 hour. Ti6Ge5 seems to be the first phase formed while TiGe2 is the end phase with the lowest resistivity. The existence of the phase Ti5Ge3 was confirmed which forms at higher temperatures than Ti6Ge5. The presence of a thin TiO2 layer was observed by TEM. Which of the phase exists or is missed depends on composition of the constituents comprising the film, their thickness and temperature of reaction. Three phases are observed to coexist on the Ge substrate, which are Ti5Ge3, Ti6Ge5 and TiGe2. A schematic suggestion is presented for explaining the coexistence of two or more phases. The concept of formation and coexistence of two phases at lower temperatures is also proposed

Formations of germanides in thin films of the Ti-Ge system were investigated by XRD after rapid thermal annealing (RTA) at several temperatures for various times. Phase formation depends on the conditions of the experiments and specifically on the thickness of the Ti film relative to that of the Ge. Considering the equilibrium phase diagram of the Ti-Ge system, if the composition is close the Ge rich side, TiGe2 might be expected to be the first phase to form and the phases present would be TiGe2 and Ge. However this is not the case. If the composition of the constituents is between the compounds of Ti6Ge5 and TiGe2, the first formation can be either one of these, but depends on how close it is to any of these compounds. However Ti6Ge5 is observed always to be the first phase. The presence of Ti6Ge5 and Ti5Ge3 is observed when the composition shifts to a location between these compounds on the phase diagram. Coexistence of Ti and Ti5Ge3 is a possibility when the amount of Ge is below the concentration of the phase Ti5Ge3, namely, when the Ge constituent is completely consumed and excess of Ti is left behind after the reaction. Temperature and time are major parameters that determine the outcome of the reactions between Ti and Ge during RTA and any of these can override the influence of the composition. XRD, SEM, Auger, TEM and resistivity were the experimental tools to study the Ti-Ge system and to evaluate the phases present under a set of experimental conditions.