Characterization of boron silicide layer deposited by ultrahigh-vacuum chemical-vapor deposition

Deposition of a boron-containing layer using B2H6 diluted with H2 on a Si(001) surface has been carried out in an ultrahigh-vacuum chemical-vapor-deposition (UHV-CVD) system. The deposited boron-containing layers were characterized by atomic force microscope and Auger electron spectroscopy (AES), and the junction depth was determined by secondary-ion-mass spectroscopy. Effective doping is accomplished before perceivable nucleation is initiated. Islands are first formed on the substrate surface at a small dose of diborane, and the grains coalesce to form a rough film for higher doses. At growth temperature above 800 °C, the film is composed of possibly SiB6, according to AES depth profiles. Correlation between the junction depth and the sheet resistance of the UHV-CVD-deposited specimens prepared under various conditions is discussed. Postdeposition rapid thermal annealing was performed to study the effect of subsequent thermal cycles on the junction depth and sheet resistance.