Nonvolatile memory and its driving method

A nonvolatile memory in which ferroelectric transistors each of which is formed by laminating a gate electrode via at least a first ferroelectric layer on the surface of a semiconductor substrate between a source area and a drain area formed on the semiconductor substrate are arrayed in a matrix, wherein:

• the gate electrode is connected to a word line, the source area is connected to a source line and the drain area is connected to a drain line;
• the semiconductor substrate is separated every column so that voltage is independently applied and is connected to back gate line;
• the potential of the source line and the potential of the drain line can be respectively set to floating potential or ground potential every line and column;
• and
• in writing data to a selected cell, a depletion layer spreads in the channel area of the ferroelectric transistor composing an unselected cell in the vicinity by keeping source/drain potential in the unselected cell in the vicinity of the selected cell a desired value and an inversion layer is prevented from being formed.

A method of driving a nonvolatile memory in which ferroelectric transistors each of which is formed by laminating a gate electrode via at least a first ferroelectric layer on the surface of a semiconductor substrate between a source area and a drain area formed on the semiconductor substrate are arrayed in a matrix;

• the gate electrode is connected to a word line, the source area is connected to a source line and the drain area is connected to a drain line;
• the semiconductor substrate is separated every column so that voltage is independently applied and is connected to a back gate line;
• and the potential of the source line and the potential of the drain line can be respectively set to floating potential or ground potential very line and column, wherein:
• for a selected cell, one of the source and the drain is grounded;
• and
• for an unselected cell at least on an adjacent line of the selected cell, in writing data to the selected cell, a depletion layer spreads in the channel area of a ferroelectric transistor in the unselected cell by making source/drain potential floating and keeping it a desired value and drain current is prevented from flowing.