Reduction of Reset Current in Phase Change Memory by Pre-Programming

摘要

Since RESET current has been a significant obstacle to achieving high density and low power consumption for phase change memory (PCM), a pre-programming method is proposed to reduce the RESET current based on the control of active area size. The pre-programming method is made of a high current RESET pulse and a DC SET pulse. The test results gathered across a 1 Kbits block of a 64 M bits PCM test chip in 40 nm CMOS process show that a maximum RESET current reduction of 0.3 mA is achieved by the proposed method. The increase of active area size of face centered cubic (FCC) phase GST is taken as the major reason for the reduction of RESET current, which is confirmed by transmission electron microscope (TEM) and a two-dimensional finite analysis.