An experimental 512-bit nonvolatile memory with ferroelectric storage cell

摘要

An experimental 512-b random-access memory based on ferroelectric-capacitor storage cells has been successfully fabricated and tested. The device was designed solely for use in process development and electrical characterization and includes onboard test circuitry for that purpose. The internal timing of the memory is controlled externally to allow experimentation with timing algorithms, hence the name 512 externally controlled device, or 512 ECD. The authors discuss the properties of the ferroelectric ceramics used in integrated circuit memories, the operation of a destructively read ferroelectric memory cell, and the organization of the 512 ECD die, including its onboard test circuitry. Finally, retention and wear-out properties of ferroelectric capacitors are discussed as they relate to design requirements.