ULTRASHALLOW JUNCTION FORMATION USING LOW-TEMPERATURE SELECTIVE SI1-XGEX CHEMICAL-VAPOR-DEPOSITION

In situ B doping and selective epitaxy on Si at 550-degrees-C in Si1-x Gex chemical vapor deposition (CVD) have been investigated for forming high-performance ultrashallow junctions. It was found that the incorp oration rate of B increased proportionally with increasing B2H6 partia l pressure, and was higher for the film with a higher Ge fraction x. U sing Si3N4, thermal SiO2, phosphosilicate glass (PSG) and borophosphos ilicate glass (BPSG) as mask film materials, about 40-nm-, 100-nm-, 15 0-nm- and 150-nm-thick B-doped Si0.5Ge0.5 films, respectively, were gr own selectively on Si(100). Using this low-temperature selective Si1-x Gex CVD, a high-performance self-aligned ultrashallow junction formati on has been achieved with a very low reverse current density, in the r ange of 10(-10) A/cm2, without heat treatment.