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.

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We report the first study of interfacial reactions of a metal with Si1−x−yGexCy epitaxially grown on Si. The Ti/Si1−x−yGexCy/Si (0<y<1.7%) contact system was studied after isochronal heat treatments from 500 to 800 °C. The results for Ti/Si1−xGex phase formation agree with recent published works. However, C incorporation in the epilayer causes a dramatic decrease in strain relaxation during the Ti reaction with the epilayer, a delay in the appearance of the C54 phase, a decreased Ge concentration in the silicide–germanide phases, and carbon accumulation (probably in the form of TiC) at the silicide–germanide/epilayer interface. Also, at high annealing temperatures, a roughing of the silicide–germanide/epilayer interface was detected for the C-containing samples. A possible explanation for the reduced strain relaxation is based on mobility of dislocations.