Nonthermal phase transition in phase change memory cells induced by picosecond electric pulse

The ultrafast amorphization phenomenon induced by a single picosecond electric pulse was studied. The RESET operations were performed on phase change memory cells with 50 nm and 150 nm thick Ge2Sb2Te5 layers by a self-built test system, respectively. The ultrafast amorphization of only 0.2 ns was observed in phase change memory cell. The dependence of RESET resistance on the pulse amplitude was investigated. Thermal simulations with a RESET pulse width of 50 and 0.8 ns using finite element method were compared. Experimental and simulation results suggest that the amorphization in phase change memory cells induced by a picosecond electric pulse exhibits nonthermal nature.