Finite Element Analysis of Dependence of Programming Characteristics of Phase-Change Memory on Material Properties of Chalcogenides

The programming characteristics of a phase-change memory (PCM) cell with a chalcogenide layer contacted by a resistive heater are investigated by finite element modelling. As analyzed in this study, the characteristics are markedly affected by the resistivity of the phase-change chalcogenide material. A higher reset current of 1.6 mA is required for the as-fabricated virgin PCM than that of 1.3 mA for the cycled PCM because of the resistivity difference of the chalcogenides in the two cases. More importantly, a chalcogenide layer with a much higher resistivity than the resistive heater is necessarily adopted for a higher energy efficiency to markedly reduce reset current to 0.6 mA or even lower while slightly increasing reset voltage.