Total Dose Radiation Tolerance of Phase Change Memory Cell with GeSbTe Alloy

Phase change memory (PCM) cell array is fabricated by a standard complementary metal--oxide--semiconductor process and the subsequent special fabrication technique. A chalcogenide Ge₂Sb₂Te₅ film in thickness 50nm deposited by rf magnetron sputtering is used as storage medium for the PCM cell. Large snap-back effect is observed in current--voltage characteristics, indicating the phase transition from an amorphous state (higher resistance state) to the crystalline state (lower resistance state). The resistance of amorphous state is two orders of magnitude larger than that of the crystalline state from the resistance measurement, and the threshold current needed for phase transition of our fabricated PCM cell array is very low (only several μA). An x-ray total dose radiation test is carried out on the PCM cell array and the results show that this kind of PCM cell has excellent total dose radiation tolerance with total dose up to 2×10⁶rad(Si), which makes it attractive for space-based applications.