Epitaxial growth of Cu (001) on Si (001): Mechanisms of orientation development and defect morphology

We describe the evolution of microstructure during ultrahigh vacuum ion beam sputter deposition of Cu (00 1) at room temperature on hydrogen-terminated Si (00 1) . In situ reflection high energy electron diffraction indicates growth of an epitaxial Cu (001) film on Si (001) with the intensity of the Bragg rods sharpening during 5-20 nm of Cu film growth. Post-growth x-ray diffraction indicates the Cu film has a mosaic spread of (001) textures of about f20 and that a small fraction (0.0014.01) is of ( 111) textures. High-resolution transmission electron microscopy shows an abrupt Cu/Si interface with no interfacial silicide, and reveals an evolution in texture with Cu thickness so as to reduce the mosaic spread about (001). Moire contrast suggests a nearly periodic elastic strain field extending into the Cu and Si at the interface. Other aspects of film growth which are critical to epitaxy are also discussed.