Patent ID: 7599278

Claim:
A method of reading data from a nonvolatile memory device comprising a recording medium which comprises a lower electrode, a ferroelectric layer to which the data is written, formed on the lower electrode, a barrier layer formed on the ferroelectric layer, and a semiconductor layer formed on the barrier layer and functioning as an upper electrode; and a probe which writes the data to the recording medium or reads the data from the recording medium while the probe is directly contacted to the semiconductor layer, wherein the barrier layer prevents a reaction between the ferroelectric layer and the semiconductor layer, the method comprising: a first operation of applying a reading voltage between the probe and the semiconductor layer while contacting a surface of the semiconductor layer with the probe; and a second operation of measuring a state of remanent polarization in the ferroelectric layer by measuring electrical characteristics between the probe and the semiconductor layer; wherein the semiconductor layer forms Schottky junction with a metallic material of the probe; and wherein the first operation comprises sequentially applying a first read voltage and then a second read voltage between the probe and the semiconductor layer, the first and second read voltages being different from each other.