Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 50: Poster II

HL 50.28: Poster

Thursday, March 30, 2006, 16:30–19:00, P3

Investigation of SnSe, SnSe₂ and Sn₂Se₃ alloys for electronic memory applications — •Kyungmin Chung, Daniel Wamwangi, Christoph Steimer, and Matthias Wuttig — I. Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany

This work reports on the temperature dependence of structural and electrical properties of SnSe, SnSe₂ and Sn₂Se₃ films studied in the search of new phase change alloys for electronic memory applications. Our results have shown large electrical contrast of a 6.0× 10⁵ and 3.9× 10⁶ for the SnSe₂ and Sn₂Se₃ alloys, respectively upon phase transition. The temperature window upon which these phase transition takes place is even lower than that of Ge₂Sb₂Te₅ (ΔT=20^∘C) for the case of the Sn₂Se₃ (ΔT=4^∘C) alloy. This could possibly suggest rapid switching. By comparing with Ge₂Sb₂Te₅ (ρ=1mΩcm) and Ge₄Sb₁Te₅ (ρ=3mΩcm), it can be seen that both SnSe₂ and Sn₂Se₃ have large resistivity values in the crystalline state of 26mΩcm and 23mΩcm, respectively. This means that SnSe₂ and Sn₂Se₃ alloys could possibly minimize the RESET current of PRAM devices. X-ray diffraction (XRD) investigations have attributed the large electrical contrast to structure transformation from the amorphous to crystalline phase. The activation energy against crystallization has also been determined for SnSe, SnSe₂ and Sn₂Se₃ alloys to 2.01±0.11eV, 1.93±0.07eV and 0.32±0.04eV, respectively. Corresponding to the structural transitions we have determined a density change of 3.79%, 20.15% and 12.4% upon annealing by X-ray reflectometry (XRR).