Growth of epitaxial germanium films on silicon using hot-wire chemical vapor deposition

We report the epitaxial growth of germanium (Ge) films from germane gas at low substrate temperature of 350 degreesC and deposition rates up to 3 Angs trom /s on crystalline silicon (Si) using hot-wire chemical vapor depositio n. In situ kinetic ellipsometry measurements reveal that deposition rate is very critical to obtain thick epitaxial films. Cross-sectional transmissio n electron microscopy and spectroscopic ellipsometry measurements yield gro wth of epitaxial Ge layer with 98% crystalline fraction. Epitaxy was also c onfirmed by x-ray diffraction measurements and lattice stress in the epilay er is estimated. Raman measurements also reflect growth of crystalline Ge f ilms without Si impurities. (C) 2001 American Institute of Physics.