CHEMICAL-VAPOR-DEPOSITION OF HETEROEPITAXIAL SI1-X-YGEXCY FILMS ON (100)SI SUBSTRATES

Thin heteroepitaxial films of Si1-x-yGe(x)C(y) have been grown on (100 )Si substrates using atmospheric pressure chemical vapor deposition at 625-degrees-C. The crystallinity, composition, and microstructure of the SiGeC films were characterized using Rutherford backscattering spe ctrometry, secondary-ion-mass spectrometry, and cross-sectional transm ission electron microscopy. The crystallinity of the films was very se nsitive to the flow rate of C2H4 which served as the C source. Films w ith up to 2% C were epitaxial with good crystallinity and very few int erfacial defects. Between 800 and 900 sccm of 10% C2H4 in He, the C co ntent increased dramatically from 2% to 10% and the as-grown films cha nged from crystalline to amorphous. In order to establish deposition c onditions for the crystalline-amorphous phase transformation, one SiGe C film was deposited as the 10% C2H4 flow was increased linearly from 500 to 1500 sccm during growth. When the C content reached approximate ly 4%, the film developed considerable stacking defects and disorder, and at around 11% C, the film became amorphous. (C) 1994 American Inst itute of Physics.