A novel cell charge evaluation scheme and test method for 4 Mb nonvolatile ferroelectric RAM

This paper proposes a novel method to evaluate the real cell ferroelectric capacitor with 4 Mb nonvolatile ferroelectric RAM which has a Cell Charge Evaluation Scheme (CCES). The charge value and the distribution of the memory cell ferroelectric capacitor can be evaluated by the CCES. Additionally, it can easily screen out weak bits which have smaller charges than normal cells by using the CCES as a bit-line reference voltage generator.