A low power 1 Mbit MRAM based on 1T1MTJ bit cell integrated with copper interconnects

A low power 1 Mb Magnetoresistive Random Access Memory (MRAM) based on a 1-Transistor and 1-Magnetic Tunnel Junction (1T1MTJ) bit cell is demonstrated. This is the largest MRAM memory demonstration to date. In this circuit, MTJ elements are integrated with CMOS using copper interconnect technology. The copper interconnects are cladded with a high permeability layer which is used to focus magnetic flux generated by current flowing through the lines toward the MTJ devices and reduce the power needed for programming the bits. The 25 mm/sup 2/ 1 Mb MRAM circuit operates with address access times of less than 50 ns, consuming 24 mW at 3.0 V and 20 MHz. The circuit is fabricated in a 0.6 /spl mu/m CMOS process utilizing five layers of metal and two layers of poly.