Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 31: Poster II

HL 31.65: Poster

Dienstag, 26. Februar 2008, 16:30–19:00, Poster D

Electrically induced phase transition in GeSbTe alloys — •Gunnar Bruns, Carl Schlockermann, Michael Woda, and Matthias Wuttig — I. Physikalisches Institut Ia, RWTH Aachen, 52056 Aachen

While phase change materials have already successfully been applied in rewriteable optical data storage, they are now also promising to form the basis for novel non-volatile electrical data storage devices. To understand the physical concepts of these so-called Phase Change Random Access Memory (PCRAM) it is mandatory to gain a deeper insight into the switching process between the highly resistive amorphous and the lowly resistive crystalline phase.

The fast phase transitions between the amorphous and crystalline state of GeSbTe-based alloys has so far often been studied using pulsed laser irradiation. In this work an alternative approach is employed to investigate this transition. Electrical pulses are used to rapidly and reversibly switch between the two states.

For these experiments a setup was built with a specially designed contacting circuit board to meet the requirements of electrical measurements on a nanosecond timescale. The influence of the pulse parameters on the change of device resistance was determined for different initial states. Furthermore the high time resolution of 0.4 ns allows investigation of transient electrical effects like the so-called threshold switching first described by Ovshinsky in the late 1960s. [S.R. Ovshinsky. Reversible Electrical Switching Phenomena in Disordered Structures. Physical Review Letters, 21(20):1450-1453, 1968.]