Incomplete Filament Crystallization During Set Operation in PCM Cells

The analysis of the phase distribution induced by the programming operation in phase-change memory (PCM) is fundamental to understand PCM functionality and multilevel capabilities. In this letter, the crystalline-phase distribution induced in an amorphous cell by the set operation is investigated at the array level. Array characterization avoids the parasitic reset during programming and allows a broad statistical investigation of the electrical performance linked to the microscopic-phase distribution. For the first time, measurements of the cell threshold voltage provide experimental evidence of the crystalline filament growth in the amorphous volume during set programming.