MECHANICAL FATIGUE IN THIN-FILMS INDUCED BY PIEZOELECTRIC STRAINS AS A CAUSE OF FERROELECTRIC FATIGUE

It is proposed that the ferroelectric fatigue is caused by alternating mechanical stresses induced piezoelectrically. It is shown that the mechanical stresses that develop upon switching are sufficient to cause significant mechanical fatigue after the similar number of cycles after which the ferroelectric fatigue is typically observed. It is proposed that the degradation of the ferroelectric properties is a direct consequence of the mechanical fatigue. It is attempted to explain some of the reported correlations between ferroelectric fatigue and microstructure, temperature, test conditions, and electrode material. It is proposed that electromigration and chemomechanical effect are essential in the mechanism of the effect of electrode material on ferroelectric fatigue. © 1995 American Institute of Physics.