KINETICS OF ARSENIC DOPING IN SILICON BY ULTRA-HIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION

Segregation of arsenic and suppression of decomposition of source mole cules during the growth of silicon by ultra-high-vacuum chemical vapor deposition is investigated. At the surface, the incidence and the des orption of arsenic balances with a small amount of incorporation. Almo st all dopant atoms segregate on the surface during the growth and the rest are incorporated. Thus, the doping concentration is governed by the competition between the growth rate of Si crystal and the segregat ion speed of the dopant. The high doping concentration was obtained at high growth temperature, because the increment of the growth rate is larger than that of the segregation speed in accordance with the tempe rature. The dependence of doping concentration on AsH3 pressure is exp lained by this model.