A Regional Model for Threshold Switching in Phase Change Memory Based on Space Charge Effect

In this paper, a regional model for threshold switching is presented based on the space charge effect in Phase Change Memory (PCM). In this model, the PCM unit is divided into two parts according to the electric field distribution resulted from the space charge effect. Then the field and voltage in each part are calculated separately and the total voltage is the sum of the two partial voltages. The physics of threshold switching is explained based on the field distribution under different current. This paper also provides the scaling trend with this model: the threshold voltage (V-th) varies directly with the thickness of phase change material (L), while the threshold current (I-th) changes conversely with L; which is consistent with the reported data.