Sputter-deposited low loss Mg2SiO4 thin films for multilayer hybrids

Mg2SiO4 (forsterite) thin films grown by rf magnetron sputtering from a ceramic target have been investigated particularly for thin film hybrids requiring a low loss dielectric layer. Understanding of the processing parameters and their correlations to dielectric properties is the main concern of this work. Fundamental parameters, such as working pressure and post-deposition annealing temperature, were found to influence phase evolution, morphology and dielectric properties. For example, polycrystalline α-Mg2SiO4 could be obtained above the annealing temperature of 500°C regardless of working pressure. The dielectric constant increased gradually while the dielectric loss showed a reverse trend of decrease with raising annealing temperature to 700°C. Dielectric constant of ~6.8 and dielectric loss of ~2.8×10−3 were obtained at 1MHz from the sample annealed at 700°C. A promising planarized thin film structure for fine line multilevel packaging was demonstrated without any significant inter-diffusion and damages between Mg2SiO4 and Pt layers. ► A report on rf magnetron sputtering of low loss α-Mg2SiO4 thin films ► Sensitivity of working pressure; producing α-Mg2SiO4 only at low pressures ► Crystallization of randomly-oriented α-Mg2SiO4 above 500°C with distinct grains ► Obtaining very low dielectric loss of