Multilayer-array growth of SiGeC alloys on Si(001)

The growth of SiGeC alloys on Si(001) in an ultrahigh vacuum chemical-vapor deposition system was investigated by means of in situ reflection high-energy electron diffraction, transmission electron microscopy, and high resolution x-ray diffraction. It is shown that when the total amount of deposited carbon exceeds a value of about 1.5%, the grown layers contain a high density of stacking faults and/or microtwins. However, such defects are found to be formed only after the deposition of a certain thickness, whose value depends on the deposited carbon amount. By realizing SiGeC/Si multilayer arrays, we show that defect-free SiGeC films with a substitutional carbon content up to 3.3% can be achieved. (C) 2002 American Institute of Physics.