In-situ and ex-situ studies of molybdenum thin films deposited by rf and dc magnetron sputtering

In-situ RTSE was used to characterize the complex dielectric functions (ε) of rf and dc magnetron sputtered Mo thin films deposited onto soda-lime glass (SLG) substrates. Distinct features in the evolution of the dielectric functions with bulk layer thickness for rf and dc films are attributed to differences in void volume fraction and Drude free-electron relaxation time. Both rf and dc sputtered Mo thin films follow a similar trend of strain variation with argon pressure. The increased grain size, as well as smoother film morphology for the dc films compared to the rf films, were both confirmed by XRD and AFM measurements. It was also observed that increased deposition pressures lead to increased resistivities for both processes, with lower values for the dc films.