Deposition, post-deposition annealing, and characterization of epitaxial Ge films grown on Si (100) by pyrolysis of GeH sub 4.

As a first step towards developing a process for producing heterostructures such as GaAs/Ge/Si entirely by chemical vapor deposition, Ge films have been deposited on (100) Si by the pyrolysis of GeH sub 4. The best films are grown at 700C and are planar and specular, with RBS minimum channeling yields of ~4.0% (near the theoretical value) and defect densities of 1.3 x 10 sup 8 cm sup (-2). Variations of in-situ cleaning conditions, which affect the nature of the substrate surface, greatly affect the ability to get good epitaxial growth at 700C. The majority of the defects found in the Ge films are extrinsic stacking faults formed by dissociation of misfit and thermal expansion accommodation dislocations.