SILICON HOMOEPITAXIAL FILMS GROWN BY PHOTO-ENHANCED CHEMICAL VAPOR-DEPOSITION FROM SI2H6

Defect characterization of epitaxial silicon films grown on lightly boron-doped Si (100) substrates by low temperature photo-enhanced chemical vapor deposition (PCVD) using 193 nm ArF excimer laser dissociation of Si2H6 in an ultra-high-vacuum (3 x 10(-9) Torr) chamber is discussed. The crystallinity was studied by in situ reflection high energy electron diffraction (RHEED), and selected area electron diffraction in a transmission electron microscope (TEM), and defects such as stacking faults and dislocation loops were investigated by TEM and dilute Schimmel etching/Nomarski microscopy. PCVD of S1 was achieved in two ways, with the laser passing parallel to the substrate or directly incident on it. For parallel laser incidence, controllable deposition rates of 0.5-4 angstrom/min were achieved. epitaxial films were achieved at temperatures as low as 250-degrees-C using photon flux densities of 10(16) photons/pulse . cm2, and Si2H6 partial pressures of 20 mTorr. The growth rates were observed to be linearly dependent on laser power. For direct laser incidence, very high growth rates (20 approximately 80 angstrom/min) were obtained. Single crystal films with a growth rate of approximately angstrom/min were obtained at a photon flux density of 7 x 10(14) photons/pulse . cm2 at 300-degrees-C and 20 mTorr Si2H6 partial pressure. The growth rates were found to be linearly dependent on photon flux density.