Preparation and characterization of Ge1Sb2Te4 thin films for phase change memory applications

• Ge1Sb2Te4 (GST) devices were prepared by an evaporation technique.
• Thin films and devices memory (RAM) applications were studied.
• IV characteristics measurements showed a large snap-back at a low voltage of 1.2 V.
• Resistance differences were of two orders of magnitude between two states.
• A large resistance window for the device may permit a reliable read operation.

Ge1Sb2Te4 (GST) thin films were prepared from their respective polycrystalline bulk on ITO coated glass substrates by a thermal evaporation technique. Thin films and devices based on GST for phase change Random Access Memory (RAM) applications were studied using temperature dependent film properties. The phase-transformation temperature of the film was evaluated by the temperature dependent resistance measurement studies using a two probe method. Using current–voltage (IV) measurements on Al/GST/ITO/Glass devices using current sweep and voltage sweep modes, confirmed the phase change of the material between amorphous to crystalline states. IV characteristics measurements using a current sweeping mode of a PCM cell with a lesser thickness of 100 nm showed a large snap-back at a low voltage of 1.2 V with a resistance difference of two orders of magnitude.

IV characteristics in a current sweeping mode of Al/Ge1Sb2Te4 (100 nm)/ITO/Glass PCM cell.Figure optionsDownload as PowerPoint slide