Thin heteroepitaxial films of Si1−x−yGexCy have been grown on (100)Si substrates using atmospheric pressure chemical vapor deposition at 625 °C. The crystallinity, composition, and microstructure of the SiGeC films were characterized using Rutherford backscattering spectrometry, secondary-ion-mass spectrometry, and cross-sectional transmission electron microscopy. The crystallinity of the films was very sensitive to the flow rate of C2H4 which served as the C source. Films with up to 2% C were epitaxial with good crystallinity and very few interfacial defects. Between 800 and 900 sccm of 10% C2H4 in He, the C content increased dramatically from 2% to 10% and the as-grown films changed from crystalline to amorphous. In order to establish deposition conditions for the crystalline-amorphous phase transformation, one SiGeC film was deposited as the 10% C2H4 flow was increased linearly from 500 to 1500 sccm during growth. When the C content reached ∼4%, the film developed considerable stacking defects and disorder, and at around 11% C, the film became amorphous.

We have used admittance spectroscopy to measure conduction-band and valence-band offsets in Si/Si1−xGex and Si/Si1−x−yGexCy heterostructures grown by solid-source molecular-beam epitaxy. Valence-band offsets measured for Si/Si1−xGex heterojunctions were in excellent agreement with previously reported values. Incorporation of C into Si1−x−yGexCy lowers the valence- and conduction-band-edge energies compared to those in Si1−xGex with the same Ge concentration. Comparison of our measured band offsets with previously reported measurements of energy band gaps in Si1−x−yGexCy and Si1−yCy alloy layers indicate that the band alignment is Type I for the compositions we have studied and that our measured band offsets are in quantitative agreement with these previously reported results.

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A study of the effects of C and Ge additions on the Cu catalyzed oxidation of Si has been performed. It was found that the addition of Ge alone resulted in a marked slowdown in the rate of oxygen incorporation; during the first three days of the experiment the rate of oxygen incorporation was 25 times higher in the Si reference sample. The Ge was incorporated into the oxide. Small amounts of C added to the SiGe compound have a more pronounced effect. Carbon concentrations of less than 2% prevent oxidation of SiGeC for periods of at least one month. Copper enhanced oxidation of Si(100) has produced oxides of several hundred nanometers in under one month.

We report photoluminescence from Si1−x−yGexCy films grown epitaxially on Si (100) by chemical vapor deposition. We observe significant energy shifts but no dramatic changes in the photoluminescence line shape caused by the presence of carbon. Using standard deformation potential theory to correct the epitaxial strain shifts, we conclude that the band gap of relaxed Si1−x−yGexCy alloys has a lower energy than the band gap of relaxed Si1−xGex with the same Si/Ge ratio. We propose an explanation of these results based on the assumption that carbon forms a resonant level within the conduction band of Si1−xGex.