Growth of Phase Pure Yttrium Iron Garnet Thin Films on Silicon: The Effect of Substrate and Postdeposition Annealing Temperatures

Growth of phase pure yttrium iron garnet (YIG) on silicon is a challenging task due to the complexity of the Y-Fe-O phase diagram, and the lattice mismatch between Si and YIG. In this paper, we report the effect of deposition and post-deposition annealing (PDA) temperatures on the structure and the magnetic properties of YIG deposited on silicon using pulsed laser deposition. Both temperatures are found to be important for growing phase pure YIG on silicon. Non-garnet phases or mixed Fe valence states are observed in films when deposited or PDA at too high temperatures, whereas partially amorphous thin films are obtained when deposited or PDA at too low temperatures. YIG thin films with bulk-like structure and saturation magnetization are obtained for films deposited at 400 °C and PDA at 800 °C-850 °C, respectively.