Solid Solubility of Nickel in Silicon Determined by Use of ⁶³Ni as a Tracer

The solid solubility of Ni in Si has been determined in the range of 900–1400°C by diffusing 63 Ni as a tracer. The activity has been measured by the surface counting method. From the plateau in the distribution of the activity, the typical values of the solid solubility of 1.6×10 17 and 5.8×10 17 atoms/cm 3 at 1000 and 1200°C are obtained. The distribution coefficient is deduced to be k =0.49exp (-27700/ R T ). k * at the melting point of silicon is 1.2×10 -4 . The differential heat of nickel in silicon at solid solution is 31.9 Kcal/mol. Retrograde solubility appears above 1200°C. The results of the solubility are fairly in good agreement with that determined by neutron activation analysis by Aalberts and Verheijke.