Patent ID: 7864568

Claim:
A semiconductor storage device comprising: a phase change thin film having two stable phases of a crystal state having a first resistance value and an amorphous state having a resistance value higher than the first resistance value; first and second electrodes provided on one side of the phase change thin film; a third electrode provided on the other side of the phase change thin film; a first transistor whose drain terminal is connected to the first electrode, whose source terminal is connected to the third electrode, and whose gate terminal is connected to a first word line; and a second transistor whose drain terminal is connected to the second electrode, whose source terminal is connected to the third electrode, and whose gate terminal is connected to a second word line, wherein a first memory cell is configured with the first transistor and a first phase change region in the phase change thin film sandwiched between the first electrode and the third electrode, a second memory cell is configured with the second transistor and a second phase change region in the phase change thin film sandwiched between the second electrode and the third electrode, at a writing time to the first memory cell, the first transistor is turned off to carry a current from the first electrode to the third electrode, and at a writing time to the second memory cell, the second transistor is turned off to carry a current from the second electrode to the third electrode.