Individual cell measuring method for FeRAM retention testing

We propose a new testing methodology to predict the failure rate for long-term data retention of FeRAM chips. The individual retention time limit for each memory cell is determined by measuring the retention time dependence on the read signal voltage using our novel test system. From this experiment, we found that the retention time limit of each memory cell obey the Gaussian distribution. We applied this method to the evaluation of 16 Kbit FeRAM test chip, and successfully predicted the failure rates for long-term data retention time as the functions of temperature and writing voltage.