Nickel dissolution into AuGe in alloyed AuGe/Ni/Au Ohmic contacts on GaAs/AlGaAs multilayer structures

T. S. Abhilash, C. H. Ravi Kumar, G. Rajaram

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

Magnetic properties of alloyed Ohmic contacts of the type AuGe/Ni/Au on GaAs/AlGaAs multilayers with n+ cap layer with different AuGe compositions and Ni-layer thicknesses are examined. Magnetization data indicate that the annealed structures are non-magnetic, at room temperature for commonly used anneal temperatures (∼ 400-430 °C) and Ni-layer thicknesses (10-100 nm). The transformation of Ni to non-magnetic phase begins at ∼ 100 °C, well below temperatures at which extensive alloying with the GaAs substrate takes place. The fraction of Ni transformed to non-magnetic phase on annealing appears to scale with AuGe layer thickness, has a quadratic dependence on anneal temperature and is time independent for time scales of minutes. The data indicate that the Ni layer dissolves into the AuGe layer at temperatures well below that at which alloying between AuGe and GaAs substrate takes place. The dissolved Ni concentration is limited by a solubility that increases with anneal temperature and decreases with decreasing Ge content from that of the AuGe eutectic composition.

Original languageEnglish
Pages (from-to)5576-5578
Number of pages3
JournalThin Solid Films
Volume518
Issue number19
DOIs
Publication statusPublished - 30 Jul 2010
MoE publication typeA1 Journal article-refereed

Keywords

  • AuGe/Ni/Au
  • GaAs/AlGaAs
  • Magnetic properties
  • Multilayer
  • Ohmic contacts
  • Semiconductor
  • Sensors

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