Two-dimensional electron gas mobility as a function of virtual substrate quality in strained Si/SiGe heterojunctions

Churchill, A.C., Robbins, D.J., Wallis, D.J., Griffin, N., Paul, D.J. , Pidduck, A.J., Leong, W.Y. and Williams, G.M. (1998) Two-dimensional electron gas mobility as a function of virtual substrate quality in strained Si/SiGe heterojunctions. Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 16(3), pp. 1634-1638. (doi:10.1116/1.589952)

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Abstract

The electron mobilities of two-dimensional electron gases in tensile strained Si grown on relaxed cubic SiGe alloys on Si (001) substrates are reported. The effects of using high and low temperature growth for the relaxed buffer layers, in an ultrahigh vacuum compatible chemical vapor deposition system using SiH4 and GeH4 gases, were investigated. We have measured electron mobilities of up to 2.6×105 cm2 V−1 s−1 for 4.5×1011 cm−2 carrier densities at 1.5 K; there is a strong correlation between surface morphology and underlying misfit dislocation volume densities which is reflected in the electron mobility. The highest mobility was achieved with high growth temperatures and high growth rates for the relaxed layers, while lower temperatures and growth rates produced samples with lower mobilities. We present transmission electron microscopy images, together with optical micrographs of the sample surfaces to demonstrate that substrate growth technology plays an important part in device performance and manufacturing compatibility.

Item Type:Articles (Letter)
Additional Information:16th North American Conference on Molecular Beam Epitaxy, Ann Arbor, Michigan, 05-08 October, 1997. N.G. and D.J.P. are supported by EPSRC.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Paul, Professor Douglas
Authors: Churchill, A.C., Robbins, D.J., Wallis, D.J., Griffin, N., Paul, D.J., Pidduck, A.J., Leong, W.Y., and Williams, G.M.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Publisher:American Institute of Physics
ISSN:2166-2746
ISSN (Online):2166-2754

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