Three-Dimensional Numerical Simulation of Phase-Change Memory Cell with Probe like Bottom Electrode Structure

A new device structure of phase-change memory (PCM) cell with a Probe like bottom electrode (PBE) was proposed and its electrical-thermal characteristics were investigated by three-dimensional finite element analysis. The programming region of the definition (GST) layer in the PBE cell is much smaller than that in a conventional normal-bottom-contact (NBC) cell after the RESET operation. The high concentrations of electric-field density and electric-current density in the small programming region of GST layer in the PBE cell have the advantages of reducing the power consumption and increasing the heating efficiency of PCM devices. Compared with the NBC cell, the RESET threshold current of the PBE cell is reduced from 1.2 to 0.45 mA and the heating efficiency increases from 28.7 to 44.1%. Therefore, the lower programming current, the smaller molten region of GST and the higher heating efficiency in the PBE cell will be propitious for developing the PCM with low power consumption and high integration density.