Nonvolatile semiconductor storage device

摘要

This invention has the purpose of providing a nonvolatile semiconductor storage device which is capable of entering multivalued storage in a FeFET unit without requiring preparation of a plurality of voltage sources. The nonvolatile semiconductor storage device is provided with multivalued ferroelectric memory cells which impart varied quantities of polarization to a ferroelectric material by applying pulse voltages having one and the same height and varied widths and consequently produce varied states of storage in conformity with the varied quantities of polarization.