One of the limits to the low power operation of MOSFET devices is the minimum subthreshold slope defined by the p-n junctions in the devices. A tunneling static random access memory is demonstrated with a supply voltage of 0.42 V, well below the minimum supply voltage that MOSFET technology is capable of delivering. The memory is produced using two Si/SiGe resonant tunneling diodes with peak voltages of 0.175 V fabricated on top of a silicon substrate.