Comparative study of hot-wire chemical vapor deposition onto (100) Si near 600°C:: Epitaxial and polycrystalline silicon films

Previously, we reported improved silicon epitaxy by hot-wire chemical vapor deposition (HWCVD) between about 600 and 650 degrees C. Such temperatures are compatible with the thickening of large-grained Si seed layers on borosilicate glasses or other inexpensive substrates. Here, we provide detailed real-time spectroscopic ellipsometry (RTSE) and x-ray diffraction (XRD) analysis of two films grown near 600 degrees C. A film grown at 594 degrees C shows breakdown to a polycrystalline phase, while a film grown at 627 degrees C is entirely epitaxial. Transmission electron microscopy (TEM) of this epitaxial film shows dislocation defects that originate at the substrate/film interface, suggesting that an optimized surface preparation could yield lower defect densities.