Scalable sensing of interconnect current with magnetic tunnel junctions embedded in Cu interconnects

A current sensor that can be integrated in back-end-of-line in the CMOS process with MTJs is proposed and evaluated. We demonstrated current sensing in Cu wires of widths of 0.24 to 2.4 μm and obtained a sensitivity of up to 4.2%/mA. Moreover, we confirmed that the combination of smaller MTJs and finer wires can suppress the effects of environmental magnetic fields.