Two dimensional electron gases in SiGe/Si heterostructures grown by gas source molecular beam epitaxy

J. M. Fernandez, A. Matsumura, X. M. Zhang, M. H. Xie, L. Hart, J. Zhang, B. A. Joyce, Trevor Thornton

Research output: Contribution to journalArticle

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Abstract

We have realized two dimensional electron gases (2DEGs) in tensile strained silicon (Si) channels between strain relaxed silicon germanium (Si0.70Ge0.30) barriers grown on Si(100) substrates by Gas Source Molecular Beam Epitaxy (GSMBE). Disilane (Si2H6), germane (GeH4), and arsine (AsH3) are used as the source gases. Compositionally graded buffer layers with a linear gradient of 30% Ge/1 μm relax the strain of the Si0.70Ge0.30 barrier layers by an amount greater than 95% as determined from X-ray diffraction (XRD) rocking curves. Dislocation densities in the vicinity of the active strained Si channels are below 107 cm-2 as determined from transmission electron microscopy (TEM) measurements. These structures have low n-type background impurity concentrations (<1016 cm-3) and the Si0.70Ge0.30 barriers can be successfully doped with a unity activation ratio in the 1017 to 1020 cm-3 range. At present, we obtain 300 K (0.4 K) electron mobilities and sheet densities in our 2DEGs of 103 (5.3×104) cm2/Vs and 3×1012 (5.2×1011) cm-2, respectively. A discussion of the requirements for growing these structures by GSMBE and the modifications needed to improve the transport properties of the 2DEGs is presented.

Original languageEnglish (US)
Pages (from-to)330-335
Number of pages6
JournalJournal of Materials Science: Materials in Electronics
Volume6
Issue number5
StatePublished - Oct 1995
Externally publishedYes

Fingerprint

Gas source molecular beam epitaxy
Two dimensional electron gas
Silicon
electron gas
Heterojunctions
molecular beam epitaxy
Gases
Electrons
silicon
gases
Germanium
Electron mobility
Buffer layers
barrier layers
Transmission Electron Microscopy
electron mobility
X-Ray Diffraction
Transport properties
unity
germanium

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Materials Science(all)
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Two dimensional electron gases in SiGe/Si heterostructures grown by gas source molecular beam epitaxy. / Fernandez, J. M.; Matsumura, A.; Zhang, X. M.; Xie, M. H.; Hart, L.; Zhang, J.; Joyce, B. A.; Thornton, Trevor.

In: Journal of Materials Science: Materials in Electronics, Vol. 6, No. 5, 10.1995, p. 330-335.

Research output: Contribution to journalArticle

Fernandez, JM, Matsumura, A, Zhang, XM, Xie, MH, Hart, L, Zhang, J, Joyce, BA & Thornton, T 1995, 'Two dimensional electron gases in SiGe/Si heterostructures grown by gas source molecular beam epitaxy', Journal of Materials Science: Materials in Electronics, vol. 6, no. 5, pp. 330-335.
Fernandez, J. M. ; Matsumura, A. ; Zhang, X. M. ; Xie, M. H. ; Hart, L. ; Zhang, J. ; Joyce, B. A. ; Thornton, Trevor. / Two dimensional electron gases in SiGe/Si heterostructures grown by gas source molecular beam epitaxy. In: Journal of Materials Science: Materials in Electronics. 1995 ; Vol. 6, No. 5. pp. 330-335.
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abstract = "We have realized two dimensional electron gases (2DEGs) in tensile strained silicon (Si) channels between strain relaxed silicon germanium (Si0.70Ge0.30) barriers grown on Si(100) substrates by Gas Source Molecular Beam Epitaxy (GSMBE). Disilane (Si2H6), germane (GeH4), and arsine (AsH3) are used as the source gases. Compositionally graded buffer layers with a linear gradient of 30{\%} Ge/1 μm relax the strain of the Si0.70Ge0.30 barrier layers by an amount greater than 95{\%} as determined from X-ray diffraction (XRD) rocking curves. Dislocation densities in the vicinity of the active strained Si channels are below 107 cm-2 as determined from transmission electron microscopy (TEM) measurements. These structures have low n-type background impurity concentrations (<1016 cm-3) and the Si0.70Ge0.30 barriers can be successfully doped with a unity activation ratio in the 1017 to 1020 cm-3 range. At present, we obtain 300 K (0.4 K) electron mobilities and sheet densities in our 2DEGs of 103 (5.3×104) cm2/Vs and 3×1012 (5.2×1011) cm-2, respectively. A discussion of the requirements for growing these structures by GSMBE and the modifications needed to improve the transport properties of the 2DEGs is presented.",
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