A high performance 180 nm nonvolatile memory cell using phase change Sn-Doped Ge2Sb2Te5 chalcogenide

Chalcogenide phase change memory has high potential to be the next generation memory, because it is a nonvolatile memory possessing high programming speed, low programming voltage, high sensing margin, high scalability, low energy consumption and long cycle duration. Sn doped Ge₂Sb₂Te₅ chalcogenide device is investigated in this paper. The conductivity of Sn doped Ge₂Sb₂Te₅ is affected by the ambient temperature in a semiconductor fashion and the activation energy for conductivity for crystalline state and amorphous state are 0.073 eV and 0.41 eV, respectively. Computer simulation reveals that the hot zone of the device is inside of the chalcogenide. Electrical testing indicates that programming time of the chalcogenide device is less than 100 ns, and the energy required for 180 nm device is less than 400 pJ. More than 100 cycles was achieved with a set/reset resistance ratio more than 300%.