Thermal stability of low-resistance Au Ohmic contacts to GeTe

Haila M. Aldosari, Kayla A. Cooley, Shih Ying Yu, Katherine C. Kragh-Buetow, Suzanne E. Mohney

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Low-resistance Ohmic contacts for phase change materials (PCMs) such as GeTe are required for devices such as radio frequency switches. The contacts must also exhibit good thermal stability since the PCM is switched by heating. In this work, Au Ohmic contacts to GeTe have been examined, including the effect of pre-metallization surface preparation and annealing on the resistance of the contacts. Although some form of pre-metallization surface treatment must be performed after photolithography to produce contacts with low resistance, the contact resistance (Rc) and specific contact resistance (ρc) were insensitive to the pre-metallization surface treatment chosen, whether in-situ Ar+ plasma treatment was used, or UV-O3 treatments followed by immersion in deionized H2O, (NH4)2S, or HCl. In all cases, Rc was 0.007 ± 0.001 Ω·mm and ρc was 1.2–1.3 × 10− 8 Ω·cm2. Thermal stability was also investigated at 250, 300, and 350 °C for 30 min. The contact resistance increased as annealing temperature increased, and changes in the contacts were observed using field emission scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy. No solid-state reaction occurred between Au and GeTe, even at 350 °C. Rather, the increase in resistance could be attributed to slit-like defects that appeared and grew in the Au layer, through which sublimation of Te occurred.

Original languageEnglish (US)
Pages (from-to)145-150
Number of pages6
JournalThin Solid Films
Volume621
DOIs
StatePublished - Jan 1 2017

Fingerprint

Ohmic contacts
low resistance
Contact resistance
Metallizing
contact resistance
electric contacts
phase change materials
Thermodynamic stability
thermal stability
Phase change materials
surface treatment
Surface treatment
Annealing
annealing
Sublimation
Photolithography
photolithography
Solid state reactions
sublimation
Field emission

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

Cite this

Aldosari, Haila M. ; Cooley, Kayla A. ; Yu, Shih Ying ; Kragh-Buetow, Katherine C. ; Mohney, Suzanne E. / Thermal stability of low-resistance Au Ohmic contacts to GeTe. In: Thin Solid Films. 2017 ; Vol. 621. pp. 145-150.
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Thermal stability of low-resistance Au Ohmic contacts to GeTe. / Aldosari, Haila M.; Cooley, Kayla A.; Yu, Shih Ying; Kragh-Buetow, Katherine C.; Mohney, Suzanne E.

In: Thin Solid Films, Vol. 621, 01.01.2017, p. 145-150.

Research output: Contribution to journalArticle

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T1 - Thermal stability of low-resistance Au Ohmic contacts to GeTe

AU - Aldosari, Haila M.

AU - Cooley, Kayla A.

AU - Yu, Shih Ying

AU - Kragh-Buetow, Katherine C.

AU - Mohney, Suzanne E.

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