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Title: Ge{sub 0.83}Sn{sub 0.17} p-channel metal-oxide-semiconductor field-effect transistors: Impact of sulfur passivation on gate stack quality

The effect of room temperature sulfur passivation of the surface of Ge{sub 0.83}Sn{sub 0.17} prior to high-k dielectric (HfO{sub 2}) deposition is investigated. X-ray photoelectron spectroscopy (XPS) was used to examine the chemical bonding at the interface of HfO{sub 2} and Ge{sub 0.83}Sn{sub 0.17}. Sulfur passivation is found to be effective in suppressing the formation of both Ge oxides and Sn oxides. A comparison of XPS results for sulfur-passivated and non-passivated Ge{sub 0.83}Sn{sub 0.17} samples shows that sulfur passivation of the GeSn surface could also suppress the surface segregation of Sn atoms. In addition, sulfur passivation reduces the interface trap density D{sub it} at the high-k dielectric/Ge{sub 0.83}Sn{sub 0.17} interface from the valence band edge to the midgap of Ge{sub 0.83}Sn{sub 0.17}, as compared with a non-passivated control. The impact of the improved D{sub it} is demonstrated in Ge{sub 0.83}Sn{sub 0.17} p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs). Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs with sulfur passivation show improved subthreshold swing S, intrinsic transconductance G{sub m,int}, and effective hole mobility μ{sub eff} as compared with the non-passivated control. At a high inversion carrier density N{sub inv} of 1 × 10{sup 13 }cm{sup −2}, sulfur passivation increases μ{sub eff} by 25% in Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs.
Authors:
; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)
  2. Institute of Material Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore)
  3. Department of Physics, National University of Singapore, Singapore 117551 (Singapore)
Publication Date:
OSTI Identifier:
22494897
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 2; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMS; CARRIER DENSITY; CHEMICAL BONDS; DEPOSITION; DIELECTRIC MATERIALS; HAFNIUM OXIDES; HOLE MOBILITY; INTERFACES; MOSFET; PASSIVATION; SULFUR; SURFACES; TEMPERATURE RANGE 0273-0400 K; TRAPS; VALENCE; X-RAY PHOTOELECTRON SPECTROSCOPY