A new candidate material for use in ferroelectric random access memory (Fram)

There are several important reliability issues that have hindered the commercialization of ferroelectric random access memory (FRAM). SrBi 2 Ta 2 O 9 (SBT) thin films have attracted much attention due to their fatigue-free properties for the FRAM applications. Recently, in elucidating the origin of the fatigue-free properties, we found that Ladoping in Bi 4 Ti 3 O 12 films can increase the chemical stability of the oxygen ions, resulting in fatigue-free characteristics. In addition to the excellent characteristics, the (Bi,La) 4 Ti 3 O 12 (BLT) films were found to have good properties for FRAM applications, including a low processing temperature and a large remnant polarization value. More recently, we also found that the BLT films have good retention properties and high resistance against hydrogen damages below 350C. These properties suggest that the BLT films should be a new candidate material for FRAM.