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HL: Halbleiterphysik

HL 34: Impurities/Amorphous semiconductors

HL 34.2: Vortrag

Mittwoch, 29. März 2006, 17:30–17:45, BEY 154

Threshold Switching by Short Current Pulses in Phase-Change Materials — •Daniel Krebs, Michael Woda, Henning Dieker, Christoph Steimer, and Matthias Wuttig — I. Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany

Changes in the optical properties of chalcogenide alloys between the amorphous and crystalline phase are currently used in rewritable optical data storage. The pronounced optical contrast upon the phase transformation is accompanied by an even larger change in resistivity. This qualifies these materials for memory concept replacing Flash in mobile applications.

While in optical data storage the heat for the phase transition is supplied by a short laser pulse, in the so called PC-RAM current pulses are employed. While the resistance changes can exceed three orders of magnitude the voltage required to trigger the phase change (set operation) does not rise exceedingly in comparison with the read voltage, due to threshold switching of the highly resistive amorphous state.

To get a better understanding of the correlation between threshold switching, structural, optical, and electronical properties we have systematically varied the stoichiometry of the investigated phase change materials and characterised there properties by different techniques including x-ray diffraction, optical spectroscopy and electrical measurements.