Czochralski growth of heavily indium-doped Si crystals and co-dopingeffects of group-Ⅳ elements

摘要

Heavily indium (In)-doped Si crystals were grown by the Czochralski method under a consideration of the effects of co-doping of electrically neutral group-Ⅳ elements (C, Ge or Sn). The In concentration in In-doped Si increased with the amount of In charged into the crucible and reached 3.5 × 10~(17)cm~(-3). The carrier concentration was at most 6 × 10~(16) cm~(-3), limited by the low ionization ratio of ～20% of In. Co-doping of C and Ge effectively enhanced the In concentration while Sn did not, which was examined in terms of the atomistic size, lattice parameter change, mutual bonding energy and solubility of group-Ⅳ elements in Si. However, no sufficient increase in carrier concentrations was detected in Si by the co-doping, and formation of some clusters or complexes was suggested.