US Patent 7920415 Memory cell device and programming methods

A memory device including a memory cell comprising phase change material is described along with methods for programming the memory device. A method for programming disclosed herein includes determining a data value for the memory cell, and applying a pulse pair to store the data value. The pulse pair includes an initial pulse having a pulse shape adapted to preset the phase change material in the memory cell to a normalizing resistance state, and a subsequent pulse having a pulse shape adapted to set the phase change material from the normalizing resistance state to a resistance corresponding to the determined data value.