Thin film magnetic memory device capable of conducting stable data read and write operations
View Patent ↗A tunnel magnetic resistive element forming a magnetic memory cell includes a fixed magnetic layer having a fixed magnetic field of a fixed direction, a free magnetic layer magnetized by an applied magnetic field, and a tunnel barrier that is an insulator film provided between the fixed and free magnetic layers in a tunnel junction region. In the free magnetic layer, a region corresponding to an easy axis region having characteristics desirable as a memory cell is used as the tunnel junction region. A hard axis region having characteristics undesirable as a memory cell is not used as a portion of the tunnel magnetic resistive element.
1. A memory device comprising:
a memory cell storing data with its resistance;
a data line electrically connected to said memory cell in a data read operation; and
a dummy memory cell producing a read reference voltage for comparison with a voltage on said data line in said data read operation; wherein
said memory cell includes
a first resistor element having a resistance varied in accordance with the stored data and a select gate for selectively connecting said memory cell to said data line in said data read operation, and
said dummy memory cell includes
a plurality of second resistor elements each having a resistance characteristic similar to a resistance characteristic of said first resistor element, and
a dummy cell select gate having a resistance similar to a resistance of said select gate, and
said plurality of second resistor elements are electrically connected with each other so that at least two of said plurality of second resistor elements are connected in series.