Internal Temperature Extraction in Phase-Change Memory Cells During the Reset Operation

The phase-change memory technology is based on a chalcogenide compound able to reversibly switch between two stable states, namely, an amorphous high-resistive state and a crystalline low-resistive one, enabling the storage of the logical bit. Such phase transition is made by electrical pulses delivered to the memory cell, able to force a temperature raise within the material and to allow the temperature conditions required for the phase change. The cell internal temperature needs accurate control, and the evaluation of the thermal resistance of the memory cell represents a milestone to develop thermally efficient cell architectures and to gain insights into the thermal properties of the phase-change material. An experimental method for cell internal temperature evaluation has been developed and then supported by the electrothermal simulation of the cell behavior during the program operation, allowing for scaling predictions.