Results of radiation effects on a chalcogenide non-volatile memory array

Abstract

We report on the progress of a recent addition to non-volatile solid state memory technologies suited for space and other ionizing radiation environments. We summarize the material and processing science behind the current generation of chalcogenide phase-change memories fabricated on CMOS structures. The chalcogenide material used for phase-change applications in rewritable optical storage (Ge/sub 2/Sb/sub 2/Te/sub 5/) has been integrated with a radiation hardened CMOS process to produce 64 kbit memory arrays. On selected arrays electrical testing demonstrated up to 100% memory cell yield, 100 ns programming and read speeds, and write currents as low as 1 mA/bit. Devices functioned normally from -55/spl deg/C to 125/spl deg/C. Write/read endurance has been demonstrated to 1/spl times/10/sup 8/ before first bit failure. Radiation results show no degradation to the hardened CMOS or effects that can be attributed to the phase-change material. Future applications of the technology are discussed.