A comprehensive study of growth techniques and characterization of epitaxial Ge1-xCx (111) layers grown directly on Si (111) for MOS applications

Mustafa Jamil, Joseph P. Donnelly, Se Hoon Lee, Davood Shahrjerdi, Tank Akyol, Emanuel Tutuc, Sanjay K. Banerjee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We report the growth and characterization of thin germanium-carbon layers grown directly on Si (111) by ultra high-vacuum chemical vapor deposition. The thickness of the films studied is 8-20 nm. The incorporation of small amount (less than 0.5%) of carbon facilitates 2D growth of high quality Ge crystals grown directly on Si (111) without the need of a buffer layer. The Ge 1-xCx layers were grown in ultra high vacuum chemical vapor deposition chamber, at a typical pressure of 50 mTorr and at a growth temperature of 440°C CH3GeH3 and GeH4 gases were used as the precursors for the epitaxial growth. The Ge 1-xCx films were characterized by atomic force microscopy (AFM), secondary ion mass spectroscopy, x-ray diffraction, crosssectional transmission electron microscopy and Raman spectroscopy. The AFM rms roughness of Ge1-xCx grown directly on Si (111) is only 0.34 nm, which is by far the lowest rms roughness of Ge films grown directly on Si (111). The dependence of growth rate and rms roughness of the films on temperature, C incorporation and deposition pressure was studied. In Ge, (111) surface orientation has the highest electron mobility; however, compressive strain in Ge degrades electron mobility. The technique of C incorporation leads to a low defect density Ge layer on Si (111), well above the critical thickness. Hence high quality crystalline layer of Ge directly on Si (111) can be achieved without compressive strain. The fabricated MOS capacitors exhibit well-behaved electrical characteristics. Thus demonstrate the feasibility of Ge 1-xCx layers on Si (111) for future high-carrier-mobility MOS devices that take advantage of high electron mobility in Ge (111).

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium Proceedings - Advances in GaN, GaAs, SiC and Related Alloys on Silicon Substrates
PublisherMaterials Research Society
Pages273-278
Number of pages6
ISBN (Print)9781605110387
DOIs
StatePublished - 2008
EventAdvances in GaN, GaAs, SiC and Related Alloys on Silicon Substrates - San Francisco, CA, United States
Duration: Mar 24 2008Mar 28 2008

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1068
ISSN (Print)0272-9172

Other

OtherAdvances in GaN, GaAs, SiC and Related Alloys on Silicon Substrates
CountryUnited States
CitySan Francisco, CA
Period3/24/083/28/08

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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