Simulation of Phase-Change Random Access Memory with Ring-Type Contactor for Low Reset Current by Finite Element Modelling

A three-dimensional finite element models for phase change random access memory (PCRAM) is established to simulate thermal and electrical behaviours during RESET operation. The RESET behaviours of the conventional structure (CS) and the ring-type contact in bottom electrode (RIB) are compared with each other. The simulation results indicate that the RIB cell has advantages of high heat efficiency for melting phase change material in cell, reduction of contact area and lower RESET current with maintaining good resistance contrast. The RESET current decreases from 1.26mA to 1.2mA and the heat consumption in GST material during programming increases from 12% to 37% in RIB structure. Thus the RIB structure PCRAM cell is suitable for future device with high heat efficiency and smaller RESET current