Pd-Ge-Au based hybrid ohmic contacts to high-low doped GaAs field-effect transistor

Joon Seop Kwak, Jong Lam Lee, Hong Koo Baik

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Effects of an intermediate layer, such as Mo or Ti, have been studied for developing Pd-Ge-Au based hybrid ohmic contacts in a high-low doped GaAs metal-semiconductor field-effect transistor (MESFET). The Pd-Ge-Au contact without the intermediate layer produces an alloyed AuGe contact at a high annealing temperature above 400°C. When Mo is added between Pd/Ge and Au, nonspiking Pd/Ge contact is formed at a low annealing temperature of 300°C. The addition of Ti, however, results in an ohmic contact with a low resistance of 0.43 Ω·mm in a wide annealing temperature ranging from 340 to 420°C. Auger depth profile and X-ray diffraction results suggest that the low resistance of the Pd/Ge/Ti/Au ohmic contact is due to formation both the Pd/Ge contact and AuGe contact through the appropriate control of Au indiffusion by Ti. The MESFET with the Pd/Ge/Ti/Au contact displays good DC characteristics. This supports that the Pd/Ge/Ti/Au contact is well suitable for application to high-low doped GaAs MESFETs due to its low-resistance and wide-process-window.

Original languageEnglish
Pages (from-to)5451-5458
Number of pages8
JournalJapanese Journal of Applied Physics
Issue number9 A
Publication statusPublished - 1997 Sept

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)


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