Microstructure and mechanical properties of heat-treated GeSb₂Te₄ thin films

Abstract

The effect of annealing on microstructure, adhesive and frictional properties of GeSb₂Te₄ films were experimentally studied. The GeSb₂Te₄ films were prepared by radio frequency (RF) magnetron sputtering, and annealed at 200 °C and 340 °C under vacuum circumstance, respectively. The adhesion and friction experiments were mainly conducted with a lateral force microscope (LFM) for the GeSb₂Te₄ thin films before and after annealing. Their morphology and phase structure were analyzed by using atomic force microscopy (AFM) and X-ray Diffraction (XRD) techniques, and the nanoindention was employed to evaluate their hardness values. Moreover, an electric force microscope (EFM) was used to measure the surface potential. It is found that the deposited GeSb₂Te₄ thin film undergoes an amorphous-to-fcc and fcc-to-hex structure transition; the adhesion has a weaker dependence on the surface roughness, but a certain correlation with the surface potential of GeSb₂Te₄ thin films. And the friction behavior of GeSb₂Te₄ thin films follows their adhesion behavior under a lower applied load. However, such a relation is replaced by the mechanical behavior when the load is relatively higher. Moreover, the GeSb₂Te₄ thin film annealed at 340 °C presents a lubricative property.

Keywords

GeSb₂Te₄ films / annealing / microstructure / mechanical properties / friction

References

[1] Ovshinsky S. R. Reversible Electrical Switching Phenomena in Discovered Structure[J]. Phys. Rev. Lett., 1968, 21(20): 1450-1453.

[2] Kado H., Tohda T. M. Nanometer Scale Recording on Chalcogenide Films with an AFM[J]. Appl. Phys. Lett., 1995, 66: 2961-2962.

[3] Gan F. X., Hou L. S., Wang G. B., . Optical and Recording Properties of Short Wavelength Optical Storage Materials[J]. Mat. Sci. Eng. A., 2000, 76(1): 63-68.

[4] Zhou G. F., Jacobs B. A. J. High Performance Media for Phase Change Optical Recording[J]. Jpn. J. Appl. Phys., 1999, 38: 1625-1628.

[5] Gotoh T., Sugawara K., Tanaka K. Nanoscale Electrical Phase-Change in GeSb₂Te₄ Films with Scanning Probe Microscope[J]. J. Non-Cryst. Solids, 2002, 29(B): 968-972.

[6] Yamada N., Ohno E., Nishiuchi K., . Rapid-phase Transitions of GeTe-Sb₂Te₃ Pseudobinary Amorphous Thin Films for an Optical Disk Memory[J]. J. Appl. Phys., 1991, 69(5): 2849-2856.

[7] Jong C. A., Fan W. L. g., Lee C. M., . Mechanical Properties of Phase Change Recording Media: GeSbTe Films[J]. Jpn. J. Appl. Phys., 2001, 40: 3320-3325.

[8] Gidon S., Lemonnier O., Rolland B., . Electrical Probe Storage using Joule Heating in Phase Change Media[J]. Appl. Phys. Lett., 2004, 85(26): 6392-6394.

[9] Ishiyama O. High-Resolution Imaging of Recording Marks on Phase-Change Film by Lateral Force Microscopy[J]. Jpn. J. Appl. Phys., 2004, 43(9): 6356-6357.

[10] Zhu S. X. Study on Probe storage Technique and Nanofabrication Method of Chalcogenide Films Based on SPM[D], 2004. Zhenjiang: Jiangsu University.

[11] Zhu S. X., Ding J. N., Fan Z., . Friction Behavior of Nanoscale GeSb₂Te₄ Thin Film in Atmosphere[J]. Tribology, 2004, 24(5): 411-414.

[12] Ding J. N., Zhu S. X., Fan Z., . Tribological Characteristic of Diamond-like Carbon Films Investigated by Lateral Force Microscope[J]. J. Wuhan University of Technology — Mater. Sci. Ed., 2004, 19(suppl): 27-29.

[13] Carpick R. W., Salmeron M. Scratching the Surface: Fundamental Investigation of Tribology with Atomic Force Microscopy[J]. Chem. Rev., 1997, 97: 1632-1194.

[14] Li D. Y., Li W. Electron Work Function: A Parameter Sensitive to the Adhesion Behavior of Crystallographic Surfaces[J]. Appl. Phys. Lett., 2001, 79(26): 4337-4338.

[15] Hirota K., Nagino K. Local Structure of Amorphous GeTe and PdGeSbTe Alloy for Phase Change Optical Recording[J]. J. Appl. Phys., 1997, 82(1): 65-70.

[16] Maugis D. Adhesion of Solids: Mechanical Aspects—“Modern Tribology Handbook”[M], 2001. Boca Raton(FL): CRC Press. 127

[17] Gao M. L., Nie S. C., Zhang S. W. Several Factors Influencing Nano-frictional Properties of Molecular Deposition Films[J]. Tribology, 2003, 23(6): 472-475.

[18] Burnham N. A., Kulik A. J. Surface Forces and Adhesion-“Handbook of Micro/Nanotribology”[M], 1997. Boca Raton(FL): CRC Press. 254

[19] Ding J. N., Chen J., Fan Z., . Molecular Dynamics of Ultra2thin Lubricating Films under Confined Shear[J]. J. Wuhan University of Technology — Mater. Sci. Ed., 2004, 19(suppl): 76-78.

[20] Li Y. P., Li D. Y. Experimental Studies on Relationships Between the Electron Work Function, Adhesion, and Friction for 3 d Transition Metals[J]. J. Appl. Phys., 2004, 95(12): 7961-7965.

[21] Wen S. Z. Nanotribology[M], 1998. Beijing: Tsinghua University Press. 167

[22] Meyer G., Amer N. M. Simultaneous measurement of Lateral and Normal Forces with an Optical-beam-deflection Atomic Force Microscope[J]. Appl. Phys. Lett., 1990, 57(20): 2089-2091.

[23] Hutchings I. M. Tribology: Friction and Wear of Engineering Materials[M], 1992. Boca Raton(FL): CRC Press.