INERT GAS RECOVERY ANNEALING OF HYDROGEN-DAMAGED FERROELECTRIC FILMS

摘要

An integrated circuit is formed containing a metal-oxide ferroelectric thin film (100, 200, 300, 601). A recovery anneal (434) is conducted to reverse the degradation of ferroelectric properties caused by hydrogen. The inert-gas recovery anneal is conducted in an unreactive gas atmosphere of nitrogen, argon or the like at a temperature range from 300 DEG to 1000 DEG C for a time period from one minute to two hours. The metal-oxide thin film comprises perorskite material like lead zirconium titanate (PZT) or preferably layered superlattice material like strontium bismuth tantalate (SBT) or strontium bismuth tantalum niobate (SBTN). If the integrated circuit manufacture includes a forming-gas anneal (432), then the inert-gas recovery anneal (434) is performed after the forming-gas anneal (432), preferably at or near the same temperature and for the same time duration as the forming-gas anneal. The inert-gas recovery anneal obviates oxygen-recovery annealing, and it allow continued use of conventional hydrogen-rich plasma processes and forming-gas anneals without the risk of permanent damage to the ferroelectric thin film.