ANNEALING OF A CRYSTALLINE PEROVSKITE FERROELECTRIC CELL AND CELLS EXHIBITING IMPROVED BARRIER PROPERTIES

摘要

A method of fabricating a ferroelectric capacitor usable as a memory cell in a non-volatile integrated circuit memory integrated on a silicon substrate (22), preferably including an intermetallic barrier layer. The memory cell consists of a ferroelectric layer (50), for example of lead niobium zirconium titanate (PNZT) sandwiched between metal oxide electrodes (52 and 46), for example of lanthanum strontium cobalite (LSCO), which forms with a crystalline orientation and provides a growth template for the crystalline formation of the ferroelectric. The intermetallic layer (44) prevents diffusion of oxygen from the bottom LSCO electrode (46) down to the underlying silicon (40). At least the bottom electrode (46) is subjected to a rapid thermal anneal at an annealing temperature above its growth temperature. Thereby, the polarization and fatigue characteristics of the ferroelectric cell are improved. Also, a similar intermetallic layer may be placed above the ferroelectric cell. A preferred composition of the intermetallic layer is a refractory silicide, especially a refractory disilicide.