bakan, gökhan atılım universityx - department of electrical and electronics engineering,, Ankara, Turkey

ELECTROTHERMAL CHARACTERIZATION OF PHASE-CHANGE FILMS AND DEVICES

34468

The reversible changes in the optical properties of the phase-change materials have made the rewritable optical storage possible which has revolutionized the dissemination of data since 1990s. For the last two decades, the phase-change materials have been studied extensively for its applications as nonvolatile memory elements (phase-change memory, PCM, devices). While the PCM devices were initially considered as replacements for the flash memory, today they promise a universal memory acting as the main memory and the storage unit. Here we demonstrate a simple alternative to study phase-change films and devices for further fundamental studies. The films are deposited using a single sputtering target and the devices are formed using single lithography, deposition and liftoff steps. The room-temperature electrical resistivity values are characterized as 5 kΩ.cm for amorphous phase, 0.5 Ω.cm for cubic-crystalline phase, 4 mΩ.cm for hexagonal-crystalline phase. The phase-transition temperature values are observed as ~150 °C for the amorphous-cubic crystalline transition and ~200 °C for the cubic-hexagonal transition while varying the film temperature from room temperature to 250 °C. Finally, microscale GST wires are amorphized by self-heating-induced melting and quenching. The electrical current density during amorphization is calculated as ~6×10^10 A/m^2.

1057

Phase , change devices , Nonvolatile memory , Electrothermal effects

Anadolu University Journal of Science and Technology. A : Applied Sciences and Engineering

1067