Design of an Initialization Circuit Used in Phase Change Memory Chip

Design of a novel initialization circuit is presented in this paper. The initialization circuit is used to supply initialization current to the first test of phase change memory chip after delivery. Inhomogeneous crystalline grain sizes appear in phase change materials used in memory cells during manufacturing process. The crystalline phase with low resistance will convert to amorphous phase with high resistance after initialization, which is called RESET the memory cells to 0. Normal RESET operation current is not high enough to RESET great grain, which deteriorates bit yield of phase change memory chip. In comparison, the higher initialization current will increase bit yield observably.