Apparatus for forming shallow electrical junctions

摘要

Very shallow electrical junctions may be formed in an oxide free surface of a semiconductor by introducing an inert or reducing gas into a vacuum processing chamber, heating the semiconductor to between 750 DEG C. and 1100 DEG C., introducing a dilute solution of a dopant gas into the chamber, and exposing the semiconductor to the gases for about 0.5 to about 100 minutes, preferably between 10 and 30 minutes. A relatively wide range of surface dopant concentrations may be achieved thereby with dopant concentration controlled independent of junction depth. Non-oxide free semiconductor surfaces may be made oxide free by first heating the semiconductor surface in the presence of the reducing gas. This technique provides uniform surface dopant concentrations and is suitable for the formation of junctions in deep trenches and other features having high aspect ratios.