INTERACTION OF PD WITH STRAINED LAYERS OF SI1-XGEX EPITAXIALLY GROWN ON SI(100)

This work describes the interaction of Pd with MBE grown strained epitaxial layers of Si(1-x)Ge(x) on Si(100), at low and at high temperatures (250-degrees-C and 550-degrees-C). Pd was deposited to a thickness of 1700 angstrom, on the Si(1-x)Ge(x)/Si(100) layers with thicknesses of 3300 angstrom and 2300 angstrom, and with a Ge contents of x = 0.09 and 0.18, respectively. Samples were annealed at temperatures ranging from 250 to 550-degrees-C. The reaction products were investigated by Transmission Electron Microscopy, Energy Dispersive Spectroscopy, X-ray diffraction and Auger Electron Spectroscopy. Strain in the Si(1-x)Ge(x) layers was measured by Double Crystal X-Fay Diffractometry. Diodes were prepared on n-type substrates, and were characterized by current-voltage techniques. The low temperature interaction is characterized by uniform incorporation of Si and Ge in the Pd2Si(1-y)Ge(y) compound (textured on the Si(1-x)Ge(x) substrate), and at high temperatures a Ge rich double layer structure formed, accompanied by strain relaxation of the Si(1-x)Ge(x) layer. The measured Schottky barrier heights were phi(b) = 0.67 and 0.65 for x = 0.09 and x = 0.18, respectively.