Forming gas annealing on physical characteristics and electrical properties of Sr0.8Bi2Ta2O9/Al2O3/Si capacitors

Abstract

Sr0.8Bi2Ta2O9 (SBT) ferroelectric film constructed on Al2O3/Si to form metal-ferroelectric-insulator-semiconductor (MFIS) was prepared to study the degradation behavior of SBT films under forming gas annealing (FGA). Although the diffusion of hydrogen ions has been detected during FGA treatment, no significant differences in the microstructure and crystalline phase are observed for the SBT film compared to that without FGA treatment. However, the diffusion of hydrogen ions leads to the rapid decrease in the dielectric constant but shows no apparent influence on the memory window of Sr0.8Bi2Ta2O9/Al2O3/Si capacitors. In addition, it was found that FGA shows a positive effect on the leakage current of MFIS in contrast to that of metal/ferroelectric/metal structure. The leakage current density of MFIS dramatically decreases as much as two orders of magnitude after FGA at 500degreesC compared to that without FGA treatment that was attributed to the reduced defects at the interface of Al2O3/Si. (C) 2003 American Institute of Physics.