Patent attributes
Methods and apparatus are provided for magnetoresistive random access memory (MRAM) bits (52, 52′) combined with associated drive or sense transistors (53, 141) to form an integrated MRAM array. The MRAM array has lower electrodes (602, 150, 160, 162) of the MRAM bits (52, 52′) formed substantially directly on a source or drain region (56, 142, 152-2) of associated drive or sense transistors (53, 141), so that the intervening vias (302, 34, 36) and underlying interconnects layers (332, 35) of the prior art (20) can be eliminated. An interconnect layer (65) is provided above the MRAM bit (52, 52′) and transistor (53, 141) combination (50, 125, 129, 133) for coupling upper electrodes (41, 164) of the MRAM bits (52, 52′) and other electrodes (601, 58, 152-1, 152-3, 186-1, 186-3) of the transistors (53, 141) to other elements of the array. Because the lower electrodes (37, 602, 150, 160, 162) of the MRAM bits (52, 52′) are formed in substantial contact with the source or drain regions (56, 142-2, 152-2) of the transistors (53, 141), a separate interconnect layer (33, 35) and/or via (302, 34) for that purpose is not needed. As a consequence, the MRAM array is more space and process efficient.
