Nb-doped Bi4Ti3O12 (Nb-BIT) ferroelectric thin films were prepared in the presence of a nonionic surfactant (pluronic P123) added as an additive to the sol solution and by rapid thermal annealing (RTA). The film annealed at the relatively low temperature of 600°C was well crystallized and showed good ferroelectricity. The switching charge of capacitors with polarization reversal increased with a large amplitude and low frequency of the applied pulse, and gradually decreased with a small amplitude and high frequency. The remanent polarization (2Pr) after subjecting the Nb-BIT capacitors to 108 read/write cycles was 45 μC/cm2, which is remarkably higher than 20 μC/cm2 observed in the initial state. These phenomena seem to appear by the presence of space charges trapped after heat treatment by the RTA process.