Low programming input, direct overwrite and synchronous phase-change random access memory (SPRAM)

The programming inputs for phase-change random access memories (PRAMs) can be significantly reduced by using voltage pulse for RESET (Vreset) and current pulse for SET (Iset) for different structures. Based upon two-dimensional electrothermal simulations, the PRAM cells can be operated by Vreset and Iset pulses of 50 ns at amplitudes as low as 0.27 V and 35 μA, respectively. The direct overwrite function can be achieved under this mode, and extra asynchronous suspending circuits are not needed.