Ion-beam-assisted growth of doped Si layers

Abstract

The growth of preamorphized silicon layers doped by multiple energy implants of boron, phosphorus, and boron plus phosphorus ions was investigated under irradiation with a 600 keV Kr+ + beam. The target temperature was set in the range 250–450 °C. During irradiation the growth was measured in situ by transient reflectivity. Boron and phosphorus at a concentration of 1 × 1020/cm3 enhance the rate by a factor of 3 and 2, respectively, whilst in compensated samples the rate is still more than a factor of 2 higher than in intrinsic or Ge-doped samples. This growth rate is characterized by an activation energy of 0.32 ± 0.05 eV which is, within the experimental uncertainties, independent of the dopant. The results are tentatively explained in terms of an interaction between generated point defects and impurities that increases the lifetime of defects at the crystal–amorphous interface.