Design of a remote plasma-enhanced chemical vapor deposition system for growth of tin containing group-IV alloys

Group-IV alloys of Ge and/or Si with Sn are challenging to prepare due to the low solubility of Sn in both of these elements. Herein, we describe a remote plasma-enhanced chemical vapor deposition (RPECVD) system designed to synthesize such group-IV alloys. Thin films of Ge, Ge1-ySiy, Ge1-xSnx, and Ge1-x-ySiySnx were deposited in the range of 280-410 degrees C on Si (001) substrates utilizing a remote He plasma with downstream injected mixtures of SnCl4, SiH4, and/or GeH4 precursors. The composition and structural properties of these RPECVD films were characterized with x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. They were found to be crystalline, oriented with the substrate, and nearly relaxed due to the formation of an similar to 5nm thick interface layer with a high density of edge dislocations and stacking faults.