Non-Equilibrium behavior of dopants during epitaxial silicon deposition using silane
Experimental studies show that the incorporation of a common gas phase dopant, AsH3 or B2H6, during the pyrolysis of silane results in a decrease in the deposition rate of silicon epitaxial layers. At low doping levels, the results are consistent with the dilute solution theory. At high doping levels, however, a deviation occurs from the equilibrium solubility conditions. Data show a reduction in deposition rate by as much as 40 percent for 10 percent AsH3/SiH4 ratios and about 20 percent for 10 percent B2H6/SiH4 ratios. The growth of retrograde junctions, where these inhibitions are most critical, are discussed.