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HL: Halbleiterphysik
HL 4: New materials
HL 4.2: Vortrag
Montag, 27. März 2006, 10:30–10:45, BEY 154
Kinetics of crystal nucleation in undercooled droplets of phase change alloys — •Dominic Lencer1, Johannes Kalb1, Frans Spaepen2, and Matthias Wuttig1 — 1I. Insitute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany — 2Division of Engineering and Applied Sciences, 29 Oxford Street, Cambridge MA 02138, USA
The demand for fast, reliable and inexpensive data storage and memory devices has led to the development of devices employing the difference in the physical properties of so-called phase change materials between the crystalline and the amorphous state to store information by switching between these two states.
While this technique is already widely used in optical devices such as CD-RW and DVD±RW, current research heads for competitive electrical memories called PCRAM (phase change random access memory).
The main challenge to turn PCRAMs into a viable alternative for FLASH chips or even DRAMs is related to an improvement in the understanding of the switching process and the crystallization kinetics.
To obtain such insight droplets of four tellurium-based phase change alloys (Ag1In1Te2, Ag1Sb1Te2, Ge1Bi2Te4, Ge1Sb2Te4) fluxed in B2O3 glass were prepared by annealing and subsequently undercooled below their liquidus temperature using a differential thermal analyzer (DTA).
The results of these measurements enabled us to estimate limits for both the crystal-melt interfacial energy and the steady-state crystal nucleation rate using the nucleation theory.