Publication date: 1 January 2016
Source:Thin Solid Films, Volume 598
Author(s): Claudia M. Müller, Ralph Spolenak
In this work a systematic in situ annealing study of sputtered Cu–Ta alloys is reported. Under equilibrium conditions Cu and Ta are completely immiscible, the metastable Cu–Ta alloys hence undergo phase separation upon annealing. Using in situ X-ray diffraction the phase evolution at temperatures < 650 °C is studied over the entire composition range and the data is assembled in a phase map. It is shown that the presence of a surface oxide layer influences the β to α phase transformation temperature of Ta and thus determines the crystal structure of the Ta-rich phase formed upon phase separation. Surface segregation of Cu necessitates the use of an alumina capping layer on the Cu–Ta/SiNx /SiO2 /Si samples.
Source:Thin Solid Films, Volume 598
Author(s): Claudia M. Müller, Ralph Spolenak