Failure analysis of Ge₂Sb₂Te₅ based phase change memory

A phase change memory device, consisting of Ge₂Sb ₂Te₅ chalcogenide, a Mo electrode and a SiO₂ dielectric layer, was fabricated in order to investigate the failure mechanism. During the pulsed mode switching of the device with a reset pulse (5.0 V, 90 ns) and a set pulse (1.5 V, 30 μs), some devices failed to reset stuck. Those reset stuck devices showed a delaminated interface with decomposed Ge ₂Sb₂Te₅ chalcogenide. A thin layer of elemental Te or a Te rich phase was observed at the interface. A working device, switched over 600 times, shows no delamination between Ge₂Sb ₂Te₅ chalcogenide and the Mo electrode and no sign or decomposition.