Electrode structures for integration of ferroelectric or high dielectric constant films in semiconductor devices

The preparation of ferroelectric and high-dielectric perovskite materials, which is performed at high temperatures in oxidizing environments, imposes strong limitations on the choice of suitable electrode materials which can be used for integration of these materials with semiconductor devices. Because of the complex compositions of the perovskites and of some of the electrode materials the two can interact and result in the deterioration of the structures. The electrode materials have, therefore, to be used often in combination with suitable barriers which block diffusion of the elements of the perovskite and of the Si device and prevent interactions between the components. These requirements can result in complex, multilayered electrode/barrier structures that can affect the crystallization of the perovskite material and its electrical properties as well as the perovskite properties during subsequent processing steps (e.g. in forming gas anneals). The present paper will review the different electrode/barrier structures that have been proposed for integration of ferroelectric thin films with semiconductor devices and discuss their effects on the properties of ferroelectric and high-dielectric materials.