Initial growth behaviors of SiGeC in SiGe and C alternate deposition

The initial growth process of Si1−x−yGexCy epitaxial thin films on Si(1 0 0) surfaces has been investigated by scanning tunneling microscopy. We attempted sequential alternate deposition of one-monolayer(ML)-thick Si0.793Ge0.207 and 0.048-ML-thick C layer grown at 600 °C in order to control C adsorption sites for the formation of epitaxial Si0.769Ge0.183C0.048 layer. In the conventional co-deposition case of Si, Ge, and C at 600 °C, it was observed that the local phase separation to Si-Ge and Si-C occurred on the surface due to the C condensation. Three-dimensional (3D) islands were formed as a result of the disturbance of conformal growth induced by defects formed on the surface. On the other hand, in the alternate deposition case, it was observed that the homogeneous distribution of Si, Ge, and C atoms led to suppression of the local phase separation, the 3D island growth, and the defect formation. As a result, the critical thickness of the two-dimensional (2D) Si1−x−yGexCy growth could be increased.