EFFECTS OF SUBSTRATE-TEMPERATURE AND ION CURRENT-DENSITY ON THE STRUCTURE OF SILICON-ON-INSULATOR MATERIAL IMPLANTED WITH LOW-ENERGY OXYGEN

Thin silicon-on-insulator (SOI) film formation during 25 keV O+ ion implantation has been investigated by cross-sectional transmission electron microscopy, Auger electron spectroscopy and scanning electron microscopy. The top Si layer thickness in as-implanted samples increased with increasing substrate temperature from 280 to about 500-degrees-C and the current density from 10 to 450 muA cm-2 at a constant dose of 2 x 10(17) ion cm-2. Substrate heated to about 485-degrees-C showed remarkable in situ annealing effects during ion implantation; resulting in the oxygen depth profile and the increase of the Si-O bonding. The SOI structure was formed in a wide range of the current density at about 485-degrees-C. Shallow holes appearing in the surface at substrate temperatures higher than 485-degrees-C scarcely influenced subsequent SOI structure formation. Deep holes appearing above 530-degrees-C made it difficult to produce the SOI structure.