Influence of the seed layer on the crystallization of in-situ sputtered SrBi2Ta2O9 films

Abstract

Crystalline SrBi2Ta2O9(SBT) thin films have been grown in-situ on amorphous SET-seed layer/Pt/Ti/SiO2/Si by rf magnetron sputtering. The effects of seed layer on the structural and electrical properties of SET firms were investigated. The seed layer used in this experiment was the 50 nm thick amorphous SET film fabricated by the same conditions as SET layer deposition except for substrate temperature. The amorphous SET seed layer was crystallized into the Bi-layer ferroelectric phase before the in-situ SET deposition at the high substrate temperature, and thus offered sufficient nucleation sites for Bi-layer ferroelectric phase. The disappearance of pyrochlore phase in SET films deposited on seed layer/Pt/Ti/SiO2/Si indicates that the role of the seed layer as a diffusion barrier and Bi-incorporation layer. By using a seed layer, it was possible to obtain the pyrochlore-free SET films with well-developed crystallinity at 600 degrees C without postannealing. The SET films with seed layer deposited at 600 degrees C showed good ferroelectric properties; remnant polarization (2P(r)) of 4.8 mu C/cm(2), coercive field (E-c) of 41.4 kV/cm.