High quality Si1−x−yGexCy epitaxial layers grown on (100) Si by rapid thermal chemical vapor deposition using methylsilane

Abstract

We have produced epitaxial Si1−x−yGexCy/Si heterostructures by rapid thermal chemical vapor deposition using methylsilane SiCH6). These layers were grown in the SiH4/GeH4/SiCH6/H2 system between 550 and 600 °C at 1.5 Torr. Suitable process conditions were found that allow very efficient substitutional carbon incorporation. No carbon cross contamination was observed. Crystal quality, chemical composition, and lattice strain were deduced from Nomarski microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, secondary ion mass spectrometry, and x-ray diffraction. Defect-free alloy layers with compositions of up to 20 at.% Ge and 2.2 at. % C were produced. The lattice parameter was tailored so that the strain in these layers gradually moved from compressive to tensile. A tensile strain of up to 0.35% was achieved.

Fabrication technology of SiGe hetero-structures and their properties

“…The crystalline quality of the films is degraded with increasing C fraction and exhibits non-planar morphology, SiC polytype precipitates, and extended defects such as stacking faults and dislocations. Therefore, film growth techniques in which the growth mode is governed not by thermodynamics but kinetics are now widely employed, such as MBE [142,143,169,170], UHV-CVD [171,172], and RTCVD [173,174]. However, it still remains an essential issue in the growth of high quality epitaxial Si 1ÀxÀy Ge x C y films with a substitutional C content higher than 3% and this limits a potential of the films to be applied widely to various kinds of devices [170,175].…”

SiGeC alloy layer formation by high-dose C+ implantations into pseudomorphic metastable Ge0.08Si0.92 on Si(100)

“…This may convert the strain state from compressive to tensile in the GeSi film. [5][6][7][8][9] Backscattering/channeling spectra for implanted samples, after implantation at room temperature and after annealing, are shown in Fig. 2͑a͒.…”

“…However, the complete substitutionality of C is not easy to achieve in all methods of epitaxial growth due to the low solubility of C in Si, and the tendency of carbon to form silicon carbide, or C-C bonds. 8 If the carbon is not in substitutional sites, the potential band gap and strain compensation effects may not be obtained. In the present study, we report the substitutionality of C in Si 1ϪxϪy Ge x C y alloy layers obtained by high-dose carbon implantation into a molecular-beam-epitaxy grown GeSi layer, and also report the effects of nonsubstitutional carbon on the structural properties of GeSi alloy layers.…”

“…11 Si 1ϪxϪy Ge x C y alloy layers have shown less compressive strain than Ge x Si 1Ϫx alloy layers due to the strain compensation or shown rather tensile strain depending on the C and Ge composition in the layers. [5][6][7][8] Because the main effect of substitutionally incorporated carbon in the strained GeSi layers is strain compensation, it is expected that thick SiGeC layers can be grown without generation of misfit or threading dislocations. However, the complete substitutionality of C is not easy to achieve in all methods of epitaxial growth due to the low solubility of C in Si, and the tendency of carbon to form silicon carbide, or C-C bonds.…”

“…[1][2][3][4] Recently, for the same potential benefits, Si 1ϪxϪy Ge x C y alloy layers have been epitaxially grown by molecular-beam epitaxy, 5,6 chemical-vapor deposition, 7,8 or by solid-phase epitaxial annealing following high-dose implantation. 9,10 Valence band offset or conduction band offset in the SiGeC layers has also been investigated and reported.…”