Surfaces And Multilayers

Applied Physics A

, Volume 54, Issue 6, pp 556-559

First online:

Alloying behavior at the AuGeNi/GaSb interface: Photoemission studies of the effects of annealing temperature

  • W. S. TseAffiliated withInstitute of Physics, Academia Sinica
  • , R. H. ChenAffiliated withInstitute of Physics, Academia Sinica
  • , C. S. Ares FangAffiliated withInstitute of Physics, Academia Sinica
  • , J. R. ChenAffiliated withDepartment of Materials Science and Engineering, National Tsingu-Hua University

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Abstract

An ultra-thin AuGeNi alloy (84%/12%/4% by weight) overlayer of 5 nm was evaporated onto Te-doped n-type (100) oriented GaSb substrates. Samples were annealed in ultra-high vacuum (UHV), with a base pressure of 10−10 Torr at either 300°C, 500°C, or 700°C for 12 h. The reacted interface was then revealed by Ar ion sputter-depth profiling. The highest percentage of Ge in the deep interface region was observed for the sample annealed at 500°C. Annealing at 500°C also leads to a uniform distribution of Ga, Sb, and Au concentrations. Results show that virtually all Au, Ge, and Ni evaporate away after annealing at 700°C. Au-based AuGa alloy formation was indicated by the shifts of Au 4f core-levels and the metallic Ga 3d peak. The small variation of Au 4f core-levels with sputtering for samples annealed at 500°C is the evidence of AuGa uniform alloying from the surface to the interface. It has been, therefore, concluded that annealing at 500°C forms a more uniform distribution of cluster size throughout the interface than annealing at 300°C or 700°C.

PACS

73.40 82.80 85.30