Low-temperature diffusion and solubility of Ni in P-doped Czochralski-grown Si

The transport of Ni atoms through P-doped Czochralski-grown (5×{}10¹⁴ cm^-3) Si 〈100〉 single-crystal wafers has been measured in the temperature range of 450 to 540 ^∘{}C utilizing an Al sink and the Rutherford backscattering technique. It is described by DC=(8×{}10²²)exp[-(2.16 eV/kT)] atoms/cm sec, where D and C are the diffusivity and solubility of Ni in Si, respectively. An independent measurement of Ni solubility in these Si wafers was also made by the neutron activation technique following an anneal at 500 ^∘{}C for 20 h resulting in a value of 10¹⁷ atoms/cm³. By invoking a clustering model of interstitial Ni with substitutional P and possibly oxygen, it was possible to obtain diffusion constants of Ni D=(6.3×{}10^-4)exp[-(0.76 eV/kT)] cm²/sec. Furthermore, the binding model also seems to provide a justification of the above-mentioned large Ni solubility.