Sm Doping Effects on Electrical Properties of Sol-Gel Derived SrBi_2Ta_2O_9 Films

摘要

We have characterized (Sr,Sm)Bi_2Ta_2O_9 (SSBT) films fabricated by the sol-gel technique on Pt/Ti/SiO_2/Si substrates. For ferroelectric-gate FET applications, a ferroelectric film which has a small remanent polarization and a relatively large coercive field is required. It is demonstrated that Sm doping in ferroelectric SBT films is effective to reduce the remanent polarization and enhance the coercive field. Sr_(0.5)Sm_(0.2)Bi_(2.2)Ta_2O_9 films (150nm) crystallized at 850℃ exhibits good electrical properties with a remanent polarization of 1.7 μC/cm~2 and a coercive fields of 85 kV/cm. These values are suitable for ferroelectric-gate FET applications.