| 摘要 |
PURPOSE:To increase a memory capacity by a method wherein the capacitor dielectric film is made of dielectric material having a plurality of spontaneous polarizations of different coercive electric field values. CONSTITUTION:First, when an electric field phi3 is applied to a lower capacitor electrode, if the initial state is a spontaneous polarization state A, the polarization is changed from P1 to P3 and, if the initial state is a spontaneous polarization state B, the polarization is changed from P2 to P3. As the value P3-P2 is smaller than the value P3-P1, if the change of the stored charge due to the change of the polarization is detected, the discrimination between the spontaneous polarization states A and B can be achieved. Then, if an electric field phi4 is applied to the lower electrode, the discrimination between spontaneous polarization states C and D can be achieved. Therefore, a non-volatile memory cell which can store 2-bit information can be obtained, so that the memory capacity can be doubled while the construction and integration degree of the memory cell are maintained as they are. |
