Methods and structures to cure the effects of hydrogen annealing on ferroelectric capacitors

摘要

A ferroelectric memory cell integrated with silicon circuitry which require a forming-gas anneal of the silicon circuitry after the ferroelectric stack has been formed. The ferroelectric layer may have a composition such that there is no space in the lattice of the ferroelectric phase to accommodate atomic hydrogen or have a composition with a Curie temperature below the temperature of the forming-gas anneal. Preferably, there is no upper platinum electrode, or it is deposited after the forming-gas anneal. A metal-oxide upper electrode serves as barrier to the forming-gas anneal, and an intermetallic layer positioned above the ferroelectric stack serves as an even better barrier. Forming- gas damage to the ferroelectric stack can be removed by a recovery anneal in a hydrogen-free environment, preferably performed at a temperature above the Curie temperature.