Surface scaling evolution and dielectric properties of sputter-deposited low loss Mg2SiO4 thin films

The evolution of surface roughness and dielectric properties of sputter-deposited Mg2SiO4 thin films have been studied. Analysis of height–height correlation function and power spectrum densities of the atomic force microscope images revealed that the growth surface experiences a difference in short-range and global roughening, indicating an anomalous scaling (super-rough) behavior. The growth exponent β = 0.9 suggests that the growth instability due to the shadowing far outweighs the effects of a high substrate temperature (700 °C). The dielectric loss tangent showed a pronounced dependence on deposition time, while dielectric constant remained unchanged at the bulk value; the changes in the grain structure via the evolution of surface scaling are suggested as a contributing factor.

► First report on evolution of surface roughness and dielectric properties of α-Mg2SiO4 thin films
► Anomalous scaling behavior of surface roughness, differently at short and long range scales
► Fast increase in film growth exponent indicating shadowing effect at a high temperature of 700 °C
► Strong thickness dependence of low dielectric loss of α-Mg2SiO4 thin films
► Successfully applicable for thin film hybrid packages requiring a low loss dielectric