On Interaction Potential, Correlation Factor, Vacancy Mobility, and Activation Energy of Impurity Diffusion in Diamond Lattice

An intuitive concept was proposed earlier by the author that for the activation energy of impurity diffusion in the diamond lattice to be smaller than that of self diffusion, there must exist a long‐range vacancy‐impurity interaction potential. The present work explores more quantitatively certain required characteristics of the potential. The relationship between the activation energies of impurity diffusion and of self diffusion, Q A and Q B, respectively, is approximately given by Q A ≈ Q B − u ( r 3 ), where u ( r 3 ) is the potential when the vacancy is at the third coordination site of the impurity atom. Most of known physical models of interaction do not satisfy the required characteristics of u ( r ), leaving that of the extended vacancy as a probable one. Irrespective of the interaction potential, the relationship between the migration energies of the simple vacancy and the vacancy‐impurity complex, H and H , respectively, is simply given by H = H + Q B − Q A − E b , where E b is the binding energy. Utilizing this relationship and published experimental data of impurity diffusion, the migration energy of simple vacancy in silicon is found to be N (0.5 ± 0.1) eV. It is also shown that the impurity‐vacancy saddle point potential will not affect Q A , contrary to common concept.