This review paper on thin film ferroelectric memory devices discusses the fabrication and properties of thin film ferroelectric devices which have applications as nonvolatile storage devices in the computers. Properties of interest for memory applications include polarization charge, switching time, coercive field and hysteresis loops. Several ferroelectric materials such as KNO₃ PZF, Bi₄Ti₃O₁₂  and BaMgF₄, are described. In particular, the work done on KNO₃, thin films at Michigan Technological University is the focus of this review.