FeRAM retention analysis method based on memory cell read signal voltage measurement

A novel retention analysis method for ferroelectric random access memory (FeRAM) has been developed, in which read signal voltages from memory cells are measured. It employs on-chip sample/hold circuits, an off-chip A/D converter, and memory LSI testing equipment. FeRAM chip reliability is estimated on the basis of FeRAM read signal voltages after retention periods of 1 day and longer. When used as a tool to estimate long-term data retention in FeRAM chips, and when used to analyze fluctuations in FeRAM cell characteristics, this method can be of significant help in improving the reliability of FeRAM chips.