A ferroelectric Pb5Ge3O11 thin film with a low dielectric constant is proposed for application in one transistor ferroelectric memories. A strong depolarization voltage on the ferroelectric capacitor with MIFSFET structures diminishes the remanent polarization significantly and, therefore, the low dielectric constant becomes very important to widen the memory window. A memory window of 3V was estimated for the MFMOS memory structure with 2000Å ferroelectric Pb5Ge3O11 and a 100Å gate oxide. In the second part of this paper, Pb5Ge3O11 films deposited on Ir/Ti/SiO2/Si substrates, by using MOCVD system, was demonstrated. Germanium ethoxide, Ge(OC2H5)4, and lead bis-tetramethylheptadione, Pb(thd)2, were used as the MOCVD precursors. The film composition, phase formation, microstructure and ferroelectric properties are reported. The c-axis oriented Pb5Ge3O11 thin films prepared by MOCVD and RTP post-annealing showed a square ferroelectric hysteresis loop with P
r of 2.83 μC/cm2 and E
of 49 kV/cm. A low leakage current of 7.5 × 10−7 A/cm2 at 100 kV/cm and low dielectric constant of 41 were also demonstrated.