Set programming method for phase change RAM, involves applying set current pulses such that magnitude of set current pulse is gradually decreased from stage to stage, for transitioning phase change cells to set resistance state

摘要

The phase change cells (PCELLS) are transitioned to the set resistance state by applying a set current pulse (ISET) to the phase change cells. The magnitude of the set current pulse is gradually decreased from stage to stage. Independent claims are also included for the following: (1) write drive circuit of phase change memory array; and (2) current controller in write driver circuit.