LASER-INDUCED INTEGRATED PROCESSING FOR HETEROEPITAXIAL SIXGE(1-X) ALLOYS

An integrated laser assisted process has been applied to prepare heter oepitaxial SixGe(1-x) alloys on Si(100) using the combination of laser induced chemical vapour deposition (LCVD) and pulsed laser induced ep itaxy (PLIE). Both processes have been carried out with 193 nm radiati on of an ArF excimer laser leading first to high quality amorphous hyd rogenated germanium (a-Ge:H) thin films by LCVD and then to unstrained epitaxial SixGe(1-x) alloys by PLIE. The optimization for depositing homogeneous, low impurity a-Ge:H films has been followed by profilomet ry, Raman spectroscopy and X-ray diffraction (XRD), Subsequent melting and recrystallization by PLIE was studied by X-ray photoelectron spec troscopy (XPS) for analysing the distribution tail of the graded SixGe (1-x) alloys and conventional XRD analysis to determine the epitaxy of the relaxed, Ge-rich, SixGe(1-x) phase, The analyses evidenced the fo rmation of thin unstrained epitaxial SixGe(1-x) layers, which can be u sed as buffer layers for the growth of symmetrically strained superlat tices.